Definitely not a pseudacanthicus, wrong head shape.
Doubt that LFS even carry other large, exotic plecos like L25, L24, L14 etc
Looks to be another one of those multiple species that arrive in a batch listed to be sold as “commons” or “sail fins.” I personally wouldn’t pay more than $10-$15 for it
Milingu seems to have made a good guess as to what it is, as usual. He’s the master of fish ID