r/M1Rifles

I field stripped my M1 and took pictures of all the drawing numbers and serial numbers I could find. I cross referenced some of them to be the correct time period but I started to get a little confused. If I’m missing pictures of parts with drawing numbers please let me know. I could NOT get the gas plug off. If they’re are numbers that require removal of the gas tube, please advise how to remove it without damaging the parts. Thank you!