Is anyone familiar with this Union hardware 15 round GI magazine? It has a type III baseplate and the "U" with serifs seems typical for Union Hardware, but the "10" lying sideways after the "U" has me stumped. Has anyone seen this before? Which M1icon Carbine manufacturer was this kind of Magazine made for? What's it worth? Is it rare or a collector’s item?

I've been using it to shoot for years, actually. I have some other GI 15 rounders mostly International Silver, in various conditions, what are they selling for these days?
Information
Warning: This is a relatively older thread
This discussion is older than 360 days. Some information contained in it may no longer be current.