I wouldn't worry about the owners. Just give it a damn good servicing if you decide to buy it - cambelts etc.
They tend to have a lot of owners for different reasons - they're not really an everyday car you can park up in town every night. Insurance killed off a lot of owners in the 80's & 90's too. I'm the 8th owner of my car, but luckily mine's had an uneventful and respectful life with all the previous owners....
As for service history - I went to Ford with mine and the service manager scratched his head and said he had no idea what to charge for a service as he hadn't seen one in years. These cars tend to be enthusiast owned now, and hence much of the servicing is done "at home...."
History gets lost, receipts get lost - it's unfortunate but it happens to 20 year old cars with lots of owners....
They're not the most practical (or reliable) car these days either.
Only question I would be asking is why is it for sale when the new owner has only had it for a couple of months.....
If it's a good one then snap it up. Just be carefull......