I haven't been there but I'm sure it's like most other off-road shops. A small retail area in the front and a shop in the back where they work. Don't expect a tour. The number of tourists to an off-road shop are miniscule. RGOR might be the exception but I doubt it.
I've been by this shop many times but it's not open to the public per se. One could always knock on the door or step into the open garage door area and see what happens. I stood outside and watched them loading the Mann once for an hour. Their not going to bark at you. If the shop is open you'll most likely see the TT, the H3's and all the support vehicles you've seen posted with RGOR activities.