Unless you're dealing with someone who specializes in doubles--and sometimes not even then!--you're probably SOL. Always good to deal with someone knowledgeable. But when you stop to think about it, how many people in gun stores are all that knowledgeable about every "niche" in the market? Someone might know collectible handguns quite well but not much about rifles and shotguns. And when you get into our fairly small niche--the sxs world--there probably aren't enough really sharp guys to put one in each and every Cabela's Gun Library.
That being said, Greg's examples are pretty pitiful.