I doubt it. REH didn't linger on characters. He wrote them if someone was buying and if there was no market for it or he had no more stories to tell with a character, he dropped it and moved on. He was done with Kane and Kull before he started Conan, and Conan started as a reworking of a Kull tale he couldn't sell. Indications form his correspondence were that he was done with Conan too prior to his suicide and didn't have any more stories he wanted to try to sell (the unfinished stuff later used by his pastiche followers was stuff he either abandoned or Farnsworth Wright had showed no interest in buying) and was moving on to other characters and stories, so had he lived, I doubt there would have been more Conan stories at all, let alone going back to revisit Kane or Kull which he had abandoned 5+ years earlier.

-M