I thought the Buck Mark Standard en route would be my first rimfire handgun, but a local Armslist listing ambushed me today. Seller said he thought it was a MkII and not wanting to take the time to research and lose out, I took a chance since it looked in decent condition. Traded some 5.56 and cash.
So it turns out to be a 1952 Standard (37xxx) with some bluing loss on the grip frame and the rest pert near perfect. It's for shooting not display and I am a happy camper.