I bought this as a replacement for a broken plastic jack plate for a Epiphone Les Paul Studio, I had eyeballed it to be a little larger than the original, which is better than smaller as it'll cover any old holes then.
Now where it didn't quite fit was the curvature, this piece was more curved than the LP, and would have needed a tremendous amount of pressure to become flush with the guitar. We are talking a single mm at max here, so it's barely noticeable.
But if you're truly a perfectionist and considering using it for the same thing as me, it might be the wrong choice.
I'm satisfied though, it looks great and classed up the guitar.