I'd imagine a FENDER EVH pickup is made by Fender and a SEYMOUR DUNCAN EVH pickup is made by Seymour Duncan.
Both pickups are produced by Seymour Duncan. However, the EVH version is a Fender/EVH exclusive and can only be purchased through Fender dealers.
there is an issue with the "Frankenstein" pick-up, the mounting ears will not fit the triangular routing of the pickup cavity, and the screw holes have to be drilled out to mount the new pckup with the foam-spring type mounting. And going to take the shim out of the nut because the strings are kinda high there and take it down some. I thought there might be an issue with guitar because i heard this before. piss me off!