You can find actual angel names that are similar to the Supernatural names in a few cases: Anna -> Anael, Balthazar -> Balthial, Zachariah -> Zacharael, but why not use these names in the first place then.
They do obviously know how to find angel names, see Inias, Samandriel etc. It can't even be laziness. I mean, if you don't want to do actual research, take the Dictionary of Angels, open a random page and point or something. *sigh*

I have read and accepted a really nice head canon for why Balthazar doesn't have (use) an actual angel name, though. So I'm good in that case.