My Dad had an OM10 (with manual adaptor) from new and was very pleased with it. In fact, it's still in a draw round at my mother's house, I had a look at it a couple of months ago and it still appears to work fine but despite it being kept at room temperature and dry conditions all its life, the light seals on the film door have turned to into sticky gunge, so it's probably best to check those when you get your OM10, Suz, before you try a roll of Vista in it?
If they have deteriorated , and the camera in in nice condition and full working order (other than the seals), then I believe it's reasonably cheap to get them replaced, so it's probably worth getting them done (especially if it was free!). My Canon A1 is away having it's light seals/traps & mirror buffer done at the moment as they were just starting to deteriorate, so I'll let you know what it costs as a ball park. Hope this is useful and the cameras are in good order when you collect them.