Matt, many AMT and MPC kits had "inserts" in them. these small, separate mold parts made parts switching possible. If you thought that parts like rims or axles looked the same, it is probably because the exact same insert was used for both kits. It has long been rumored that Jo Han tools are useless due to the theft of many inserts.
Every time I saw a clip of Barris talking about the Monkeemobile. he used the phrase "my Monkeemoble" not "when I designed the Monkeemobile". He let the listener assume the origins of the car. I always took it that he was referring to the fact that he had bought the car. He chose his words as carefully as a lawyer would.
Most MPC MoPar B body kits shared an almost identical chassis pan. The original 65 Coronet (molded by MPC but sold by AMT) has a pan almost the same as the 67-70 Charger annuals and even the Dukes of Hazard and 70 Coronet. I don't have too many B boy variations, but I know that these are almost the same. The AMT 65 Coronet has full rear wheel wells and the front sub-frame has the wrong shape, but everything else seems the same. I don't know when MPC took off the wheel wells or corrected the front, but I don't think it took too long.
There was a very long and very informative seminar at GSL this year. one of the SLC club members even did a demonstration. A presenter that does a 3D printing blog said that a printer will soon be on the market for $275 and the club member mentioned that it is a good idea to have a computer specifically dedicated to the 3D printer
There was a lot of discussion on software, too. It is supposed to be put on the website so look for it and get comfortable before you start.
What I learned is that I will NOT be doing 3D printing. It would take me forever to learn the software.
Another presenter had a different approach: he did three view drawings on paper, hired somebody to convert them to 3D files, then had a printing surface make the part. he then made RTV molds and resin cast the parts. For me this sounds like the way to go. This guy also did a seminar on resin casting that also should be on the GSL site. I HIGHLY recommend thae anyone interested in 3D printing view one or both of these seminars.