At least in our area, the chances of finding anything interesting in an LFS tank are next to nothing. First, there really aren't any LFS left in the area (well, there are a couple)...and second, they buy from the same farms, wholesalers and sources that hobbyists (in our club at least) are able to access.
It used to be that LFS were the hub of the hobby. They were relatively numerous and competed on (among other things) bringing in new and cools stuff. They'd take trade-ins and juvies from trusted local sources. That's really just not the case today (with very few exceptions, especially if you're giving fish away).
On the other hand, a nearly unlimited list of uber-rare species are available with the click of a mouse and a credit card payment. It's no longer really a hunt. It's all there and available so some of the thrill is gone.
The "mixed African" tank is a scourge of the modern cichlid hobby... but that's another topic
Matt