I'd say get him to send you a picture - as far as I'm aware, none of the engines used on the GVs had any inspection plates on the front. If I assume it's the 2.5 liter V6, they are known for leaking around the timing cover if it has been removed and not properly resealed - quite a bit of work is involved in getting access there, so the price would have to be very attractive, maybe it's time to just move on.