Personally I recommend getting a generic bolt and lock nut in either UNF or UNC I just didn't see the point of using lock washers or trying to find BSF nuts and bolts. I did buy the factory floor screws but never used them, Slotted heads, give me a break it's not the stone age, I went with a 10mm hex head, although my floors are aluminum checker plate they are still quite slippery with snow on the boots so the hex head screws just give a little more grip. The cost of buying generic hardware was very low but worth the money in time saved.
1971 series 2a 88, series 3 trans, Fairey OD, owned since 1978.