No, they're two different mods; one of them is created by Antistar (WMX) who is the creator of Weapon Mod Kits from Fallout 3. He also has an optional module for Modern Weapons, and may implement Melee weapons in the future. WME is essentially the same thing; the key differences being WMX mainly focuses on weapon efficiency in terms of durability and less spread, and WME is (from what I have seen) damage focused. In some cases, I thought of it as over powered when I had it.
It rally depends on what you want.