I fitted early forks onto an 06 model, I think the internals were slightly different but still able to swap around. The wheel spindle/axle maybe different
Only shows 1 mount but that could be due to the shape of the frame https://www.cmsnl.com/suzuki-gsx1100f-1990-l-e01-e02-e04-15-16-17-18-21-22-24-25-34-39-53_model13748/partslist/FIG-04.html#results
I think you mean the spacer in my picture. There's 1 each side of the engine, top rear mount. https://www.cmsnl.com/suzuki-gsxr750r-1986-g-usa-e03_model16088/partslist/BLCK0018.html#results & https://www.cmsnl.com/suzuki-gsxr750r-1986-g-usa-e03_model16088/partslist/BLCK0010.html#results
Factory pro have some examples of different setups using the 38's what have you fitted?
Main jet? Pilot jet? Needle position? Filters? Any Slide holes filled? Thanks