Ive asked as well because someone else asking if other rotors work and so far, nothing will because wilwood offsets the rotors to fit the larger caliper.Wilwood likely has a proprietary offset on their rotor hats so that you are married to their branded rotors. I asked them for the rotor specs/dimensions to compare them to available OE replacements and they never responded. Perhaps one of the vendors on here could take some measurements of both the Wilwood and R1 Rotors and answer this question.
It is entirely possible though assuming another Rotor brand got a hold of a wilwood one to measure