Yes they are legal to own. This just shows they were manufactured during a period of stupidity in American history.
New HK USP'S are sold with the m&p only mags.
I could make a list of a bunch of guns i have, or "have", or wish I had. Why would one feel compelled to provide that infornation freely? Do you feel the need to show off? Is it some immature game of oneupsmanship?
Why do you feel it necessary to list your guns?