Hi guys - my son bought a '94 MIM Strat 2nd hand, but the tremolo arm is missing. I want to order him a replacement, but I'm puzzled. As far as I know, US Strats have 10-32 size arms and all other (MIM, MIJ) have M5 size. Before I ordered the M5 arm I double-checked with a proper M5 screw and there is no way that that is the correct size. It won't even fit the small hole, so I can't reach the screw thread. Tried an M4 screw for reference and that is too small, it's not gripping the thread. What is going on here? Has the bridge been replaced with a US bridge and should I get a 10-32? Is there any way to tell what bridge this is?