Ok, I finally got the rotor replaced. I ordered 2 non slotted rotors on Thursday and each one was delivered to a different store on Friday, SMH. I was able to pick them up this morning and just got to work on the car. For now I only replaced the side that was knocking. The knock is currently gone, I will continue to drive the car this week to see if it stays gone. I am using the same pads in the same positions that were knocking before the rotor swap. If it doesn't come back, then I will swap on the other rotor. The car isn't pulling or anything weird so I didn't see an immediate reason to change the other side. Besides, if this doesn't work I can a least return one rotor.
Here's a little bit of info some may find helpful. When I went to get new wheel seals, there was only a listing for drum brake seals. I got them anyway and they were the same as the disc brake seals that came in the kit. I figured the sealing surface would be the same because it's a drum brake spindle, I wasn't too sure about the overall diameter of the metal ring though. Thankfully it all fit together perfectly.
1967 Mustang, mild 351W, 750 Demon, MSD, Pertronix, long tubes, Dan williams built top loader with Hurst shifter, #550 coils, 5 leaf mid-eye springs, 3:55's, CSRP disc brakes.