Definitely a TO-3 mount not c mount.
Junktronics is a member here. Just look up the members list and it should have his store/ phone #. He may be able to give U advice. Could also try OneStopLaserShop, or post to Steve Roberts (laserGuru) either here or on google groups- alt.lasers. Laser Sam may even chime in over there to give U some help if you are very clear and specific about the problem and solution needed.