Strange that an LFS would sell an animal and not have it identified :notsure:
There are three things that make me guess Heteractis magnifica, one the color of the column, two is the blunt sometimes dual colored tentacles, three it seems to have a smooth column
However, the Heteractis magnifica, should have many more tentacles to it than this one does.
If it were Heteractis magnifica, I warn you they can get really huge and I mean mongo.
With the open disk shot in the second pic, it has tentacles spaced more like the BTA, but then again it seems to have many more tentacles surrounding the capitulum than your typical BTA.
Lets give it some more time to get accustom to your tank and see how it looks then.
It's just a guess and maybe other will give their opinions as well, after all, I'm just learning like everyone else.
Thomas