Karl is a member here, and happens to actually know-it-all :thumbsup :love
Cheaper to buy one, than accurately replicate it with the same process used. The top one was rereleased. I have an original release I picked up for $80 4 years ago, and it appears to be stamped metal parts, with a striker that lights up the red plastic in the window. Mine is "frozen" :cry, but I love it.
If I were going to take a non literal wag at it, I'd run over to tap plastics and buy scrap lexan. Laminate acrylic sheet, rough shart the outline with a band saw, and shape the trigger assembly and the handle contours with a dremel. The large barrel, I'd make from PVC pipe, and the smaller barrel extension I'd use K&S metal tubing. The series of cooling fins, could be stamped individually from K&S metal sheet between male/female forms shaped from lexan and pressed in a bench vise maybe. Make each fin sepately, like the original.
Looks like fun.