GCI has groove the length of the rail & GCII has shorter piece lengths. If I remember correctly.
That would be 100% correct Because of the pain in the ass getting the extrusion molding lined up on the GC1's, they shortened the extrusion molding into shorter pieces on the GC2's, 4 short pieces on the sides, and 3 on the head skirt, foot skirt had one piece on each end skirt, and 2 pieces on the ball box. The bolt on side skirts didn't start until the true GC3's came out. The early GC3's were for the most part left over GC2 parts, making it more of a GC2 1/2
Glen