1st gen. bolt plug ??

[Slamfire]

 I'v posted this in gun smithing also,,, need a screw in fireing pin plug for a 1-2 gen bolt ( 76),,but a bolt from a 73,,1st-2nd gen,has the same screw in plug,,,,OR,,if I knew the thread count of the plug I thing I can make one,,( just looking at some pictures) any info. would be a big help.






 smok'm if y'a got'm,,Hootmix.