O-D;
I have a 10ga Lefever, SN'd 10515 so in the same area. This should be a cocking rod gun, so has cocking cams in knuckle joint. Mine don't really look like wheels or rollers, but perhaps were some variations in how they were made. Mine is an E & has the E after SN on frame table & before te SN on bbl flats. It has a scroll design engraved on the side plates. Mine has the side pivot top lever, but some of these rod cockers had the thumb push opener. I have seen an F grade 12ga thumb push gun & it only had the border engraving as you mention on this one. The frame sure sounds like an F but have no idea why it has the E on the bbls. I assume, as you didn't mention otherwise the SN's match other than the E & F. I have been out of buying/selling for several years, so not really up on current prices, but those old rodcockers are really neat guns, not that plentiful particularly in anything smaller than 12ga. In the condition you describe I would personally think that a very reasonable price, but hopefully someone more currently knowledgeable will reply.
Incidently Cornell Publishers has a reprint for an 1895 LAC catalog which details this basic action.
