These will only work on import guitars with metric bridges, and in most cases they will only work when both the thumbwheels AND the bolts are exchanged. Gib...n bridges are made for 6-32 bolts/wheels, and M4 is too big for US bridges. Stewmacs' bolts are M4 x 0,75, which is a highly unusual thread, as regular coarse pitch for M4 is 0,7. Overall quality is good, but measure before you buy.
I used the thumb wheels on the org SG posts and found them to be very loose. Not wishing to make more work for myself I opted to use what I had before. Maybe you need to state that you need to use these posts & thumb wheel's together and not mix with org Gibson fittings.