I ended up finding a knife shop up the road from my house, https://www.centennialguns.com/ off 23 mile and DW Seaton in New Baltimore, that had a CMMG survival kit (lots of extra parts). Figured it would be good to have them around for a rainy day.
Got home, sat down, tore into the bag, then out of the corner of my eye, spotted the lost pin. Life is strange.
Thank you everyone for your help! Especially the kind offers from many of you to help a man in need.