Are you talking about Ork Deff Dreads?
If so, yes.
It has 2 DCCW base, so +1 attack for having two weapons (pretty sure that's covered in the rulebook), and then for each extra one it says you gain +1 attack, which is in the unit profile.
Damnit, should probably refresh threads before replying.
Actually, the FAQ covers Ork deff dreads. They have 2 DCCWs but the extra attack is already factored into their profile according to the FAQ, so if you buy 2 more DCCWs then it goes up to 5 attacks.