Long bolts you can always make shorter. Its been a while since I dealt with Retro friction shifters but I recall the bolt was retained some how. That said I did replace a damaged screw on a braze on lever by just using another screw the same size (but it looks a little different) There maybe different thread pitches on screws but I dont think Italian or French are different. Only common odd pitches on phillips screws are Japanese Motorcycles of the 70s and I am guessing they are ISO standard.
BOB FREITAS
suns out!! in MILL VALLEY, CA USA