I stopped by my local "fun store" this afternoon and found an enigma. They have a box of what seems to be GI 30s. BUT---these mags are a light silver I have never seen before. The finish is very different from all other I have seen or used. They are new mags, and they are not refinished. After 10 insertions into a new Bushy---no marks on the mag--not a hint. The surface is much harder than any sheet metal I have seen--and yes I have used "Bird song" and others. There is no info on the mag body, and the base plate has:
CAL. 5.56 MM
Made in USA
The follower is the old black GI, the spring is the old style also. And yes the body and plate are Alum. The owner of the store says he got them 8 or 9 years ago from a factory rep.
What do you all think?

Troy,
I used the "MATTIES" in NAM, read the post. These are alum GI or better quality, same quality spot welds, and congigurations as in Center 92's. The finished alum body is so hard and slick you could not load without putting the bottom on a table. The only thing a magnet would grab is the spring. I use a dial calp & mic. on the mag wall---it is thinner than a GI mag.

You are correct, I forgot and left that off the post. There is a number on the base plate. This look and feels like one of the best mags I have seen in 40+ years of shooting. Thanks for the help.