In giving this the "5 minute, in depth, all inclusive, internet search evaluation" (grin), they do seem to be different species. LiveAquaria also lists them as two different species -
http://www.liveaquaria.com/product/prod_display.cfm?c=497+499+631&pcatid=631
http://www.liveaquaria.com/product/prod_display.cfm?c=15+2971+626&pcatid=626
However, I don't think it's quite that simple. First off they look very much alike and second one sells for about twice the price. I can easily see where the lower priced one gets sold as the higher priced one. I can also see this going the other way around too. Many LFSs are not experts in this area, and may list the anemone that they have by whatever name they got on the invoice.
If your going to get a large anemone like this, I think either would be good in most cases. The big exception would be when you want to have a species of clown fish and the same species of anemone that it normally hosts with. Even that doesn't guarantee anything, since clowns often have their own ideas on the subject and choose to host in something completely different.
