Oldest OM-2 bodies can be problematic. OM-2 production started at serial number 100,000 and continued to somewhere around 600,000, when production chnaged over to the 2N. I'd avoid any OM-2 below 250,000 serial number simply for the amount of work they need to be made reliable. If it's up around 500,000, perfect, as it's got almost all the improvements before it became the 2N.

John
http://www.zuiko.com