While hard, positive, facts are somewhat hard to come up with on Lefevers, my guess from the fact it only has the one number on each bbl, might be an indication they did in fact come as a set. It appears that when a gun went back to the factory for a 2nd set or an "Upgrade" to a later action type it was customary to add a 2nd SN. Does this gun have an '07 patent among the ones on trigger plate. If not is likely an '06 gun. Appears to be an H or G, hard to say for sure from the pics. Just looking at the pics doesn't appear likely to be deeply pitted, may well just be mostly cosmetic damage, of course that would have to be considered in the price, but may not affect it's shoot-a-bility.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra