EULA is the wrong term here, as the people looking at source code usually are not end users.
Legally, it makes no difference either; copyright does not need to be declared explicitly.
Basically, all you achieve is a lower risk of people accidentally violating your license terms. You'll have to decide how important that is to you.
I'd say the best compromise is to put a very short header containing a link (absolute URL as well as relative within the project) to the full license text into each source code file. That way, anyone who cares about the license knows where to find it (ideally, people who're willing to pay massive license fees; you certainly want those people to be able to contact you!)
