I think if they ask for a charge (like they do with steering racks etc) it's unlikely they'll sell one without. The problem with the starter going, assuming it is, there are days when it's fine and days when it isn't. Personally I'd go for having the contacts replaced if the seller is still around, that's what I did. I had times when I would have to try several times before it engaged, other times it was ok. From what you've said, and if the battery is good, I'd be surprised if it was anything other than the starter.