M1 Garand bolt heat lot numbers....question

Maybe someone can steer me in the right direction on a source to determine correct heat lot numbers for post-war SA bolts. Up until last Saturday, the "latest" heat lot I have observed was a "YO2" on 65 series bolt. I was at the CMP north store on last Saturday and bought a 5.4M SA field grade. I looked it over and in addition to the nearly new barrel dated 10-54, it looked like it had mostly correct parts on it. I did not look that closely at the bolt, except to see it was a 65 series and that would have been right. ANYWAY... to make a long story a little shorter, the bolt carried a heat lot mark of "Z2", one I had never seen before. Anyone have any info on these? TIA, Ben.

My understanding was that the Z2 would have been used from about 5.8 to 5.9, about the same time as the Z1, Z3, A14 (can go back to 5.3), A15 (can go back to about 5.4) and Y01. I'm not a post war guy so don't hold me to the fire on this. I do like them post war rifles though. Mighty fine shootin' irons.

Known M1 garand Bolt Heat Lots

I have a new bolt Well its was still in the packaging. Its J-1-A heat lot. Can I assume that these were made as replacement part?

Do these help at all?

Regards,
Badger