this is a really good fish store. they take good care of there fish and there bettas are in good water. i have never heard of anyone having to return a fish because of an ilness or death and i have never seen any signs of ick or anything else on any of there fish. so i think i trust them pretty good.
I get my plants form an lfs. I live in the city and there are 5 or 6 different lfs that are small mom and pop ops. one store takes good care of their fish, even feeders, but the two tanks they have live plants in smell kike death. As a result i wouldnt but plants from there althought i would buy fish (like i need more)
So like i said if you dont know enough to spot poor plant quality at that lfs i would qt the plants. you dont have to throw them away or anything and by all odd the plants are prolly fine but its good to get in the habit of putting them in qt