"Effectively", it works the same.
Essentially, the PXE rep determines "which boot image should I get?", and then goes for that. So if you rename the WIM files, then - yes - that will affect your PXE booting as well.
I don't have issues with hacks like this by and large - the only caveat is that I always try to make sure that people don't shoot themselves into their own foot. So - by renaming the WIM-s be aware that even your BIOS devices will try to load the 64-bit WIM ... which CAN cause issues.
So - just "be aware" / prepared (and *TEST* ) ... find the "nastiest / oldest" device(s) you can/have, and see how they do ... if they work fine with your hacks, then you should be OK by and large. If anything's going to fail, likely it'd be those devices (and chances are you know exactly the make/model that's causing you the most regular headaches anyway).