this tiny brass plate fell out of my guitar

[Jimbilly]

I got the '89 Jem back from the 'shop' yesterday, took the neck off to see the ink stamps, took the pickguard off to clean around under the edges and see the wiring, and de-oxit the pots. After stringing it up and after initial setup, while re-aligning the trem bar retainer spring:

this little brass plate fell out from somewhere, the guitar setup just fine, but there's this mystery, what is this from/for?

 

[veatch]

Looks like the bottom of a Floyd Rose bridge saddle. Those can fall out. Remove the string lock block, put the shim back in, put the lock block back in, and you should be fine. I've had some that just won't stay on, so i replaced the saddle. 

[Dave Scepter]

String height adjustment shim