How do i check Synchro in a gearset?

[2g Strat]

So I have this trans that i bought for the ring/crown gear. It was dirt cheap, untested, unknown mileage.

So i open it up, to my surprise its remarkably clean! Minimal debris on the drain plug magnet. No scoring on anything, bearings/races look smooth, gear teeth look the same as my 30k mile gearset.

I dont know what to look for with the synchros... Is there a way to check them visually?