I'm afraid I'm not going to be much help to you, but thought I'd at least bump this up for you. I've got no experience with Gehl machines (little enough with Bobcat for that matter)
but one thing I would look into is dealer support. Is there one close by? Do they have a decent parts dept.? Maybe drop by and B.S. with them for a while, as they're likely not selling this particular machine they might not push the “product” as hard as they would if it was on their lot and may give you a more honest opinion.
If there is no dealer close by, I would be more inclined to pass this one by, unless it's very cheap and has the appearance of being in very good condition. Lift the cab and open all access panels and check to see how clean it is, accumulated muck can hold back any leaks from reaching the ground hiding potentially expensive repairs. Ask for service records or reciepts for parts and repairs if available.
If you decide to go for it, I'm kind of thinking this might make you our resident Gehl expert,
so hopefully you'll stick around and keep us all informed on how it goes.