No small lettered ones have turned up yet, just the Large.
The mag bodies are similar to the Armalite marked one described by Roscoe Snyder:
https://www.milsurps.com/images/impo...tuff0123-1.jpg
https://www.milsurps.com/images/impo...tuff0173-1.jpg
https://www.milsurps.com/images/impo...tuff0183-1.jpg
https://www.milsurps.com/images/impo...tuff0193-1.jpg
https://www.milsurps.com/images/impo...tuff0202-1.jpg