I would make sure that they actually have one in stock before going any further. I've seen too many sites that show that they may have something but haven't updated their sites in years.
Dumas kits aren't easy to work on. The wood quality for their kits is usually of poor and difficult to work with. The hardware kits weren't that great 30 years ago. I've got a buddy that has a .60 version and never got it running right.