I think on the McGowen "drop in" barrels, they leave them stamped on purpose. Mine is also, bought new through Northland:

[img width=600 height=450]http://i490.photobucket.com/albums/rr268/slowpokeslim/P1050331.jpg[/img]

I believe it would only be faced off the chamber end if it was originally bought as a blank, and finished by a smith.