Moser is a lefty that TB just traded for and is very high on, yes he can play the right side effectively but Buffalo has a couple players like that too. I think they are more in the market for a true RHD.
This is more in the sense of TB hopping in on that action to land Tuch. Pittsburgh is probably more willing than Buffalo to accept futures, so I could see it working if the goal is for Buffalo to not get worse. After all, Rakell is outproducing Tuch this season and his contract might actually age pretty well with the cap situation. Tuch on the other hand could be looking at 7-8 mil by next summer, and there's a risk he doesn't remain with Buffalo.