A very fine condition , not modified 12 gauge Westernfield/Browning patent marked shot gun is available for $150. I think this gun is a Stevens 520 BUT the top of reciever is not completely square but has a ridge across it ; different than a square back. I am interested in this rare Browning 1902 patent with the locking lug thru top of reciever and bump forward to release pump action . Since Stevens produced this gun in WW1&WW2 as a military arm I presume they were good? Is this ridge on any Stevens recievers? Does anybody know if these guns are good?