When I bought the blade, I thought, "Woah! Cheap masterwork sword! Sweeet!" I mean, who wouldn't? And, I looked, but I couldn't find it in the museum. Could someone please add it?

Its just a masterwork sword, theres no big special thing about except thats it crafted better basically, anyone could get a masterwork sword if they bought one. It doesn't need to be in the museum, only prizes and the likes go there.

Yep. Its just a masterwork. Its nothing special.