10COAC Replacement Stem

I'm looking for a replacement stem for a 10COAC movement and am having trouble finding the model stem or a cross compatable stem. I inherited the watch from my grandfather and have fixed the movement but he had lost the stem a long time ago. If it helps it's off of a 1965 commander D, I can't find a parts list in the database for it. Any information would be greatly appreciated, thank you.