OffsetGuitars.com

Hi,
I recently got a JMJM with a staytrem bridge upgrade and a vintage tailpiece which I do not think is staytrem but I can't tell. It was recently professionally set up so I don't want to take it apart but I wonder if there might be a serial on the back? The guy I bought it from does not know the year and I can barely see inside the trem sleeve because it's so shiny that flashlights just reflect and make it impossible to see if there's a thread.
Is anybody able to tell by sight what era this would be from? I can't figure out what kind of tremolo arm I need and I already tried this one from amazon https://www.amazon.com/gp/product/B003B ... UTF8&psc=1

here are pics of my JMJM
https://i.postimg.cc/hGVHJ0KH/IMG-2095.jpg
https://i.postimg.cc/kXDzNCnN/IMG-2098.jpg
https://i.postimg.cc/qv3FYG6z/IMG-2099.jpg
https://i.postimg.cc/9XLsq0jF/IMG-2102.jpg

thanks!

You'd have to take it off to see underneath to be reasonably sure what it is. Some people can pick some trems from the lock button bevel/metal. But there's always the chance that the arm collet was swapped. So looking underneath is more reliable. You can do that without taking the strings off by wrapping them near the neck heel (to keep them in place) and then loosening them right off. Yours doesn't have the more oval shaped MIJ collet hole in the top plate, so not surprising that the Amazon MIJ arm didn't work. See the old thread link below for what the major lock trems look like underneath. While you say "vintage" it looks like it could just be "well used". It looks to me like it could have the lock screw in the bottom of the collet for screw-in arms. The Am Pro and Classic Player trems are screw in arms (so threaded collet); the rest are push-in.
https://offsetguitars.com/forums/viewto ... 5#p1525263

Riley below has good information on which arms fit which trems. If screw-in, Riley says CP has 10-32 thread and Angela says Am Pro has 10-32 thread. But their arms have different Fender part numbers, which may or may not mean they are not inter-changeable. I don't recall anyone here trying that.
https://darrenriley.com/product-categor ... -tremolos/
https://reverb.com/au/item/12697691-fen ... 7710465000

Awesome, thanks for all the resources and info! I had an inkling it might not be truly vintage...

Yeah, just looks like an AVRI/AV65 to me.

Looks like an AVRI trem to me as well.
A metric sized trem arm will not fit as it's too wide (Allparts, Squier, CIJ,MIJ, Fender will not fit)

I don't think it's a MIM trem as the collet hole is not round on these (it's more oval as on the MIJ/CIJ)
So a threaded trem arm will not be needed.

You'll need a AVRI trem arm for this. Don't forget to order the trem tip as well as these are sold seperatly.
Angela.com usually has both items (if you're located in the US, they are a good option)
But I'm sure other sources for these might be closer to you.

In any case, there are no serial no's on the inside of the trem unit's. The vintage Fender ones did have some small markings (if I remember corectly) but non of the re-issues do have any markings or serials on the inside of the unit.