PHOENIX — The launch edition of the GMC Hummer EV is already the most well-equipped trim the brand offers on any vehicle, but early buyers are decking out the pickup even further.

“Every Hummer is loaded up. Every single one,” said Howard Drake, dealer principal at Buick-GMC Sherman Oaks in Southern California.

Nearly all of Drake’s 17 Hummer Edition 1 customers have spent $4,000 for an exterior lighting package and the hard power-retractable bed cover. That’s on top of the $112,595 price, including shipping.

Many customers also have purchased the tailgate audio system and a kit to store the Hummer’s roof panels in the front eTrunk.

Drake’s dealership sits near star-studded Hollywood and Beverly Hills, Calif. Most of his initial Hummer buyers are household names, including renowned chef and restaurateur Wolfgang Puck.

More than 66,000 less famous consumers have reserved a spot in line for the pickup or the Hummer EV SUV, which will go on sale in 2023. GMC says that’s enough demand to cover production into 2024.

From December through March, General Motors delivered 100 Hummer pickups, and the vehicle is “running a lot richer than we thought,” Duncan Aldred, vice president of global Buick and GMC, told Automotive News during a media drive last month in Scottsdale, Ariz. “It’s turned out great for everyone.”

Part of that richness has been driven by add-on accessories. GMC says customers are spending between $2,000 and $4,000 to spruce up their already-loaded Edition 1 models, and as lesser trims begin to launch from late 2022 through spring 2024, customers are likely to add even more options and accessories.

The Edition 1 is the top-line trim and includes every available factory option. Customers can still add accessories.

Launching with one standard trim has “been part of the magic to get it to market so quickly,” said Matt Mallino, marketing and advertising manager for the Hummer. “We have a very wide portfolio of up to 200 accessories [that are] Hummer EV-specific.”

After Edition 1 reservations sold out, 80 percent of the reservation holders “are basically ordering the Edition 1 spec — the top-of-the-line vehicle, everything on it,” Aldred said.

Popular accessories include the hard power-retractable tonneau cover for the pickup bed — in place of the soft cover that the Edition 1 comes with — and the lighting package, which has front off-road auxiliary lights, interior footwell lighting, rearview mirror project lights and tailgate step lighting.

Hummer buyers are spending about twice as much on accessories than buyers of the gasoline-powered GMC Sierra pickup and Yukon SUV, Aldred said.

Dealers can earn a margin of about 12 percent on add-on options, Aldred said. Dealers’ margin on accessories varies, but Drake said his average is between 25 and 30 percent on the Hummer.

The accessory frenzy is reminiscent of the way buyers of the previous gas-guzzling Hummer brand jumped on opportunities to personalize their trucks, said Will Churchill, co-owner of Frank Kent Motor Co. in Arlington, Texas.

“We were a Hummer dealer back when the Hummer was originally around, and it was an accessory monster,” he said.

The take rate on accessories is welcome but not surprising. “The opportunity is definitely there,” he said, especially for the 30 orders of later-trim Hummers he expects at his Chevrolet-Buick-GMC store.

“The launch edition came one way. It came with every option under the sun, and then it was up to the individual to personalize it with accessories,” he said. “As they launch new models, they will begin taking options off of those vehicles. Then the customer has the opportunity to add.”

Beyond accessories, the sheer demand for the Hummer has motivated GM to accelerate production. Momentum hasn’t slowed even as a growing number of electric pickups, including the Chevrolet Silverado EV and Ford F-150 Lightning, has been revealed since the Hummer unveiling in October 2020. So far, the conversion rate for Hummer reservations to orders exceeds 90 percent, Aldred said.

Drake likened the Hummer to a “10,000-pound Ferrari that can go over rocks.” The uniqueness of the speed and capability has appealed to his customers.

“I don’t care if the guy pulls up in a Porsche GT3 or a supercharged Rover or anything in between, they’re like kids when they get into that,” he said. “Just thrilled.”

According to GMC, about 70 percent of consumers who have reserved a Hummer pickup or SUV would be first-time EV buyers, and 75 percent would be new to the GMC brand. About 80 percent say they will drive off-road at least once a year, and 30 percent plan to go off-roading monthly. Buyers who live in California, Florida and Texas make up 30 percent of the reservations.

“This is beyond our hopes in terms of what we are achieving,” Aldred said. “Our best plans, our upside plans … this is going better.”