One quick thing to look at right away is the two cross-pieces on the centerstand. On early Bracebridge Street centerstands the lower cross-piece will be about .500" diameter, on the later AMC centerstand it will be about .875". Also the early stands might have a small diameter lever that curls around the exhaust pipe you press down on with your foot to put the stand down which comes right off the left foot of the stand, the later AMC stands will have a much heavier lever that comes off of where the lower cross-piece is brazed in.
An early featherbed stand may have two casting numbers on it, one for each cast side of the stand, 17173 and 17174. A later AMC stand I have has only the 17173 number on it, and a stand a good friend of mine has from a 1953 wideline looks identical except it has no casting numbers at all and it also never had a cast-in lever for the foot but some other arrangement that was fabricated and added.
From looking at the wideline and slimline stands directly their measurements suggest they are functionally interchangeable despite small differences in detail over the years, they have the same outside width at the top where they go between the frame lugs and bolts and they have the same length from the center of the pivot holes to the bottom of the feet, about 10 inches.