Ok, got the reject buttons today from Betson and they fit great. I also got my T3 1/4 Wedge Socket from Happ using the item:
42-0351-00 LAMPHOLDER,F/PLASTIC MECH HOLDER
If anyone is interested in getting LEDs from Happ that will fit that socket, here is the part number:
91-10WB-123R LED T3 1/4 WEDGE BASE 12VDC 3 CHIP RED
However, superbrightleds.com has a better selection.
I wired one of the sockets into my PC power last night and the LED glows a superbright red. I am using a 4 cluster RED LED. As soon as I get the mechs in, I'll wire up the coin switches to accept coins. I also ordered new springs for the reject button assembly from Bob Roberts. They should come sometime Saturday or Monday.