That's interesting. My Gardmaster Canada Dollar album has slots for the 1950 and 1951 Arnpriors, but for the '52 dollar it only has slots for two varieties: "water lines" and "no water lines." Now I see you're right that Charlton does list a 1952 Arnprior (and notes that unlike the other Arnpriors, the '52 was deliberately created).
Well heck. I'm just gonna consider my set complete since all the holes in the album are filled.