Yes, yes, yes, and NO!
They are my wheels, but back in the day they were supposedly ANSEN'S but I have seen many called AR or American Racing.
They are a 13 x 5.5 and the backspacing sounds right.
I have seen some with DIFFERENT center holed for HUB CENTRIC cars, but min are LUG CENTRIC with NO SLOP whatsoever.
I'm SURE his wheels have been drilled out so the larger lug-hole diameter is 2 mm larger giving him a 2 mm larger bolt pattern overall of 4 x100... He is still retaining the 4x98 pattern as well.
Alas... they are NOT A STOCK 'unibolt' wheel but they do indeed function as one... and you should not have any trouble as they will self center on the studs and you just need to have a proper SHOULDERED Lug-NUT with a WASHER to install them.
Here is a REAL unilug wheel by Cragar where there are SLOTS instead of holes and they fit the usual 5 x 4.5, 5 x 4.75 and 5 x 5 inch bolt patterns. (5 x 5.5 early Ford requires a separate wheel...)
Alas... here are example of the washers that fit IN the slots or recesses, built into the wheel's center. All they really do is work with the lugs as a finished product... but they don't have to. As I said before, the wheel will self center...
Note the last washer on the lower right, this one fits on TOP of the wheel center as in the AR wheels we are talking about. It does not fit IN a recess.
So... if you like those tires and wheels... I'd make an offer. The tires alone look like a good $200 bucks leaving $250 bucks for the wheels. You need to figure shipping though and all they need to be is placed face to face in pairs and tied together... but ya also gotta ascertain WHY he is selling these... as Federals have been known about 50% of the time as being out of round and difficult or impossible to balance.
Rudy Mortero here is the only one I know that got four good 185/60x13 Federals the first time. Maybe they "fixed" them... Returning these would not be cost effective...
If you are suspicious then make an offer for just the wheels and barter until you are comfortable if you need to replace a couple of tires...
Good luck with your decision.