I would say there is a good chance this boat has FG & foam stringers but it is hard to know for sure without manufacturer documentation or taking core samples. There will be wood under the engine mounts, in the transom, and in the sides of the hull. Either way, most all boats have wood somewhere. Wood is moot if the boat is in good condition with good maintenance history and the transom and stringers are solid when you rap on them. To put it another way, I wouldn't buy a boat that had not been kept clean and maintained well even if it had no wood in it.
I would press the owner(s) for maintenance records and details on repair history or at least find out where they had the boat serviced and see if that shop will confirm general service history for you. Of course, take it for a test drive and watch for unusual noises and watch for water production in the bilge area or oil production in the engine and outdrive (i.e. be watchful for more oil after the test drive than before the test drive). I would also look for water in the outdrive oil by draining 2-3 cups out the bottom, not the top, as water will settle to the bottom of the drive - you are looking for milky or melted caramel looking stuff. If you have a boat friend that is not a party to this transaction have them come along as an extra set of eyes and ears.
There are some good checklists for things to check on this site if you want to do more. In my mind, as long as the stringers and transom are solid and will bounce a hard-plastic screwdriver handle nicely, the hull looks clean and clear and has no waves/seams/ridges/color variations that indicate prior repairs, the engine and outdrive don't make oil and run smooth and quiet (carbureted small blocks will wiggle a little at idle until they get warmed up), the boat is clean inside and out and you can get comfortable with the maintenance history your are more than likely going to be ok. Also might try lightly tightening the front motor mount lag bolts just to be sure the wood in the motor mounts is solid. A mechanical inspection to include the above plus a compression test, vacuum test, engine alignment check, gimbal bearing and u-joint inspection, and ignition check (spark plugs have the right color soot and no rust, distributor cap terminals are in good shape, etc.) would be even better. If you want to look hard for bargaining chips check the trailer hubs for smooth operation and proper adjustment. Also check the DOT code on the tires to make sure they aren't over 5 years old (trailer tires on the whole generally don't fare well past about 5 years whether the tread looks good or not).
Four Winns makes a good boat and the "stable-vee" hull with the extended planing surfaces on the back make for a quick-planing boat that handles very nicely on the water. I really enjoy my little Four Winns.
