Gold Crown 1,2 & 3's all used the same style of attatchment of the castings and the same style of frame. 1 & 2's used pinned slate a few 3's did before going to Brazil. 1 &2's used screws to haold all trim and the castings are real thick aluminum. 3's used afew nails and a unique mounting of the trim the casting's are thin wall pot metal.
The GC4's use 2 captive furniture style screws or clamp method for there casting's thin wall pot metal agian but with thier logo cast on to it. The trim pieces held on the same as the 3 both a pain to take off to refinish 1 &2's much easier. The Frame was redesigned to look like 4x5" lumber looks like ostrand board somtimes 18 point leveling screw system.
THe 4 is were Brunswick started over pricing themselves the GC5 looks nicer play's great and is a little cheaper with better looks but still twice the price of most tables made here in the USA. I think thats why you see more Metro's and Gibson in tournament with brunswick so consumers can afford them around the $6,000 range instead of $10,000 for a GC.
I could go on but hit me up with a pm if you like
Craig