That's what I was thinking. I wanted to be sure there wouldn't be any electrical problems related to using a modern flash on an older camera. I seem to remember reading that there can be problems up to and including damage to the flash or flash circuit on the camera. However, that might be with a specific camera and flash combo...
The OM1 will work fine with any electronic flash unit either via the standard hot shoe or the co-ax plug, set to X-sync. of course. The shutter will sync. at speeds up to 1/60, marked in blue on the shutter speed dial. Sadly, no TTL, but any computer flash will provide auto exposure.
Some/many older flashes would have a very high voltage across the contacts when used. This can damage more recent cameras with electronic circuits (especially digitals). This may be what you read about.