Al (IRIPN)
"Give a poor man a gun and he can rob a bank.
Give a poor man a bank and he can rob everyone."
Anon (Heard on the radio!)
http://www.flickr.com/photos/smart4lec/
There are few lens makers in Japan outside of the camera makers and a large number of independent maker names. Badge engineering in lenses, IIRC, went on before the more recent fashion for 35mm and digital compacts. Lens designs would be sold around these companies and they would have different cosmetic touches applied to differentiate between 'brands'. Underneath they could be, and often were, identical.
If you're going to look for a Zuiko F/1.8, try to track one down which says "made in japan" on the front. The lens was subject to at lest four different variations though out its life, and the 'made in japan' ones have the best image quality. Not that the other ones are bad.
The two main things which can blight OM10s as they age are rotted seals round the door-aperture and 'sticky magnet' syndrome. Both can be fixed at home if you're a bit dexterous.
Hope you enjoy it.