The other stories in "Bob Swift" has also these same smiling faces with long chins, but the faces have no resemblance to a signed story in "Pay-Off " #1, 1948, so there could be a misplaced credit on the originals, or Butts radically changed his style in two years.
Boyd Magers has Clem Weisbecker as artist on Rod Cameron, but the realistic horses in this issue are far from the crude ones by Weisbecker, see Jungle Girl #1. His are very similar to the horses in Bill Boyd Western, with large snouts and oversized hooves. Very uncertain credits.