Hello:
Thanks, Jim for responding:
Perhaps Mr. Marcot will know which rifling equipment was used on Spencers.
An experienced collector/dealer, David Stavlo at Lodgewood, looked at these photo's.
He said that the sort of blemishes IN the metal of the receiver are common on sporters and caused the gov't. to reject some otherwise serviceable receivers purely for cosmetic reasons.
Edited 21MAY19 to add "blemish" info. R/JKT
Regards,
Kevin Tinny/El Supremo