Tom,
Oops, thanks for correcting. I was referring to the follower guide, of course
For those with Mauser Parabellum magazines: The follower guide is usually brass. If, by any chance, it is of an aluminum color/texture (the guide, not the follower, ahem), the chance is there that the follower guide has been made from a modified NWM head stamped 9x19 aluminum blank.