The marks are consistent with some dummy trying to unscrew the barrel from the receiver without the proper tools...Don't ask me how I know...
It is easy to skew the receiver by doing this...And a real beetch to get it straightened and aligned afterward...
The marks will affect the price, and as Gerry says, it's not all that rare to begin with...IMHO, if you get a $100 for it, you is doin' good...
