The pickups are a different size, in the jagmaster they are regular humbuckers, the jazzmaster has huge single coils. The jagmaster has none of the switches on the upper bout that the jazzmaster has, thus none of the routes. The Jazzmaster pickgaurd has holes for the bridge piece holding the saddles, whereas the jagmaster bridge stops at the edge of the tremelo plate.
hmm if i route do you rekon it wil decrease the value of the guitar? i mean this will definately become a collectable.
people will be like check out that mij jagmaster!
i guess the wisest idea is to change the nut and replace the pickups with p90s. they look like jazzmaster ones.