I've never been able to find out any details about this company. It's not known if Musial was actively involved in the company or just lent his name for marketing purposes.
I have one of these in my collection (not the same glove as your's, but a different model). Musial was a Rawlings endorser throughout his career and these apparently came out after his playing days had ended. They seem to be late 60's to early 70's.
That's not much to go on, but it's all I got!