For anyone interested I'll share my current situation and experience for any others who happen across this thread. I picked up the wheels I had been looking into; unfortunately the buyer did not know the brand or backspacing/offset. Turns out they were 4" backspacing 15x8 black D hole steel wheels. The more I looked into it I found that CT&W was inscribed on the wheel which is the manufacturer for Cragar wheels. I called up Cragar and confirmed these were in fact theirs but their D hole design is essentially identical to other brands.
After test fitting the wheel, it very narrowly missed the front calipers. I mean very narrowly. I'd guess it has a clearance of 2mm at best and this is with three year old pads. New pads would definitely rub; in my opinion it's not worth it. I'll more than likely be going a different route now as 3.75" backspacing will probably create to much fender rub in the front and the look is not quite my taste. I mention this because I figure most all D-hole steel 15x8 wheels will run into this issue and I'm assuming the similarly designed Soft 8 wheels.
If you're thinking about going this route in the future; stick to 3.75" backspacing for 15x8 steelies or go up to 16s and have fun with the backspacing. If you found aluminum wheels in a 15x8 with a semi-large offset they'll actually probably work because it's the recess in the steel wheel around its circumference that causes the issue; most alloy wheels don't incorporate this into the design.