Those are Mopar A Body wheels. They used the 5X4" from 1963 to 1972. Those small bolt pattern are pretty sought after. You would probably be wise to sell them and find what you want in the size and bolt pattern you need. That small bolt pattern used either 13" or 14" wheels, so they might not even clear big drums. What size are these wheels. The A Body Forum would be a good place to sell them. FORABODIESONLY.
The Mopar A body is the 63-72 Valiant, 64-69 Barracuda, 63-72 Dodge Dart, and the 70-72 Plymouth Duster.
If you redrill them and find they don't work for you, no Mopar guy will want them, rendering them useless. And it's very doubtful that they fit over disc brakes with the 5.5 pattern or the bigger drums that you probably have.
Finding 15x4" slotted mags is getting harder, I've been looking for some time now. I've found 3 sets with 5 on 4" small Mopar pattern. (and some chevy patterns) EDIT: not running any brakes, so clearance won't be an issue. (going on an Altered) anyway, I figure I have 3 options, 1. Buy aftermarket hubs with correct bolt pattern. 2. Re-drill hubs bolt pattern and decrease size of hub for wheel center. 3.125 to 3.00" 3. Re-drill wheels bolt pattern and fill in existing holes. There is an area on back of wheels that will accept 5 on 5 1/2" holes, but will be very close to existing holes. I'm leaning towards re-drilling hubs and using screw-in 1/2 x 20 studs. (either double ended or Allen head) BUT, hubs don't have alot of material between bearing races either.