Just purchased a new May 2012 G21SF to go with my Oct. 2009 G21SF. I like to have pairs. Looking at them side by side, I noticed a couple of differences. The 09 has the patent stamp on the right side and no lanyard hole and the 2012 is just the opposite. No patent, but a lanyard hole and then there is the differences in barrel chamber hood markings, but I know about that. Glock is getting as fickle as S&W in the 1990's when it comes to design changes!