That looks like an edge alright. But to use it in the jem jr I'm afraid you'd have to do some routing. The stud spacing may be off too which would require plugging and redrilling them. The best drop in replacement I've heard for the jr seems to be the gotoh 1996t
Lol okay, didn't know about the stud spacing - I've only seen the difference when it comes to the edge zero and lo-pro, but different can of worms then as you say. But I really thought switching the trem for an edge or lopro would be a bit more invasive as people warned me about when I was considering a jem jr for upgrading, but I guess not then - might consider doing it myself some time then
I've seen the same "warnings" countless times lol. I've done this a fair amount of times, its not nearly the amount of work I've seen people claim. If you'd like, I've got dimensions of various floyds as well as direct measurements from various bodies I can pm you if youre interested. The lo-trs model ibanez's should basically be a drop in replacement; the lo-trs is bigger lol. The edge 3 is a teeny tiny bit smaller and a bit more contoured, so the body shape matches that which causes the "lack of fit". The edge pro 2 one is irritating because it fits the cavity just fine, but where the block goes doesnt fit at all. THAT SAID, its been a few years, but last time i did that particular upgrade, I realized that part of the guitar is invisible, its a cheap korean ibanez, and no ones gonna care... so I smacked it with a chisel and carved out enough room real fast lol.
Now, in full fairness and full disclosure, despite having done this like a dozen times, I DID encounter an issue once. Im not sure what the deal was; I wish I measured the thing, but I had a korean saber that wouldnt fit an edge because one of the saddle lock bolts was sticking too far out the back and it ran into the body. It was again, like less than a mm, but that IS a very visible and noticeable spot, so youd need to route that for sure. That said, if you lack the skills or equipment to do that, I 100000% promise you you can take that body to a luthier and tell them what you need and they will charge you like 10 bucks for the job.
99.99% of guitars featuring any kind of floyd rose is going to have 74 mm stud spacing with 11mm inserts. REALLY old floyd systems use these studs that actually screw into the body, they are utterly terrible lol; but still, 74mm spacing. I cant think of a single reason why a guitar wouldnt have this spec, but Im giving myself the out for when invariably that one guy comes in "WeLLLLL on my 1982 jackson obscurity, the spacing is SEVENTY SEVEN mm" lol.
edit: Oh yeah, the 1996t is an amazing floyd rose, and a great recommendation regardless of what fits or not.