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Jim VBOK. I had to look it up.
Mickey Cochrane did it in 1925. (He only had 6 HR's for the entire season.)
Butch Henline had done it in 1922, but he had 112 ABs in 1921 which I think was enough to disqualify him from rookie status (but I don't know for sure, because that is one of those rules they change from time to time.)