Looks to be in fabulous condition - aperture works smoothly, the A-M switch is fine, focussing is smooth through what must be about 270 degrees. Stamped 'Made in USSR', serial #097392 - I read somewhere what the serial numbers meant, and seem to recall those starting with zero mean something, but can't remember what...
It weighs a ton!
Now all I need is my M42-Nikon lens mount adapter!
Hand-held lens on the D50, took a while to hit the focus.