M7? I thought only Vespa used those on their scooters. Go see your nearest Vespa dealer they will have a small stock of M7 nuts and rods. But good luck finding a stainless steel M7 nylon nuts! Are you sure it's a metric size, I suspect it's a UNC or UNF size really as M7 mostly disappeared in the 60s. See
those guys for a good source of one-off bolts.
As for shackle pins, I don't think so. Just measure your shackle and buy a replacement with a captured pin