I did a search on the web and found no reference to the (A), circle A or simple 'A' designation. I have used this lens (sans 'a') many times. On the enlarger that I have used it -- a Beseler 45 -- it had fall off issues on the corners for 4x5 when enlarged full frame, but allowed for easier (less head elevation) cropped enlargements from 4x5's than a 150mm. This might be an enlarger specific issue.

On the flip side the lens looks very clean and the price is certainly v good (new at b&h the lens goes for 350.00).