Hello. I have just joined Photrio, having been a member of A/DPUG in the past. I have also just acquired a very clean and functional OM1 MD with a 50/1.4 lens. The seals need replacement and I am awaiting delivery of a kit before I can run some film through the camera. The meter is working with the correct battery so will see how long it lasts. I already have two Adaptall wides, a 17 and a 24-48 which I will be able to use on the camera.
The serial number is sub-300,000 so I assume it has the foam over the pentaprism to protect the meter cells from stray light but there is no marking visible in the viewfinder so I guess it is still OK. Read some horror stories on the web. There does not seem to be any mirror damping foam apart from two very slim strips at the top corners of the mirror box which were very soft but not gooey. I am wondering if they are actually the edges of the foam over the pentaprism mentioned above. The mirror is after all controlled and damped by the piston device which was such a stellar feature when the camera was introduced.
The size of this group indicates how well this range of cameras is appreciated today and of course Olympus play on it in their advertising and naming of their digital offerings.

Puzzled no more after taking the top plate off and cleaning the gunk off the pentaprism all as per the video. Also established that there are indeed four tiny bits of foam to damp the mirror as well as the air pistons. They are the very devil to replace and I have only done a passable job but at least they are now in place and the mirror doeas seem a little quieter.