Peace Dollar question

sliderider

I was just looking at my 1921 Peace dollar and comparing it to later years and noticed that on the reverse, there are 12 rays running down the eagles back on the 1921 whereas there are only 11 on later years. My assumption is that the last ray near the tip of the tailfeathers was removed to accomodate the D and S mintmarks that weren't needed in 1921 since Philadelphia was the only place they were minted that year. My question is this, since the Philadelphia mint didn't use mintmarks, and would have had no urgent reason to retire the 1921 dies, are there or could there be any VAMs where the reverse of 1921 was used on a 1922??