Quite a few of those humpbacks could be from having an Emag, and upgrading the body and valve etc when the Xmag came out. It was an upgrade package you could order directly from AGDE.I don't mind that, there's several for sale on AO and PBNation in the $800-$1100 range. But the only ones with a humpback frame are the European ones The ACE configuration on Euros are also more sturdy.