I'm not sure that anyone has specifically reported that yet. The release from Tuesday is hard-coded to not install on the 5,1, but I think a few people with the know-how have gotten it running. But I'm not sure if any of them had 4,1->5,1s.
It should work though. If Apple really wanted to hard code an exclusion for 4,1->5,1 flashes then they could have/would have done it with High Sierra. I don't think they really care.