They probably are "post ban" since I can't see any evidence of wear on them, they look absolutely brand new to me. This however goes right in line with the previous responders to this thread who said that even Glock cannot identify which are pre - and which are post - ban. The whole thing is just freakin ridiculous if you ask me.
+1. In terms of AR mags if there is no date stamp it's extremely
difficult to determine when the mags were made. Many USGI mags have
date stamps, but not all vendors, even the domestic ones, were making
mags with date stamps. There were also a buttload of magazines
imported from other countries. (Namely, Taiwan and England).
Further compounding provenance of AR mags is the fact that there are
probably at least a half dozen or more companies that make/sell the
things, and probably several others that made mags under different
names, etc, companies that changed names, or companies that were
basically sales fronts for manufacturers. When you have the world's
2nd most popular assault rifle, the market needs an assload of
magazines to feed them.
Just because it looks new is also not an accurate indicator. I remember
seeing AK mags coated in oil in early 2004 that looked "new". I also
saw vendors at gun shows in 2003 selling non-leo marked AR mags in
virtually new condition, with little wear. Friends of mine have also
bought mags in the mid 90s without issue. This leads me to believe
that there never really was a supply shortage of these things. Even
during the ban, 30 rnd AR and AK mags were not difficult nor expensive to
procure. Yeah, some guys were gouging at $30 a mag, but you often
could find mags selling for $11-15 too. All the while, Glock 21 normal
cap mags were fetching like $70-80 a piece, due to relative scarcity.
I guess what I'm driving at, is someone selling "new old stock" AK or
AR mags would not surprise me at all. Problem is now for MA dealers
is that the bigger distributors of that stuff don't really keep track of
provenance anymore, because the majority of the states in the US no
longer have this issue.
-Mike