DrPhil and mrcallow
Thank you both.
I see DrPhil's point that the "A" does appear on the lens shown and may just be a mystery. I think the seller is honest as he has a positive rating on over 1000 items sold.
the second area of concern for me is the fall off factor which mrcallow confirms. The D-5 XL has plenty of elevation so a "good" 150 will better serve my needs.
Thank you both for keeping me on track.
OT mrcallow: Way back when I was in High School one of our rival sports teams was Ferndale HS. I went to what was then Southfield. "But that was a another time in another country and the bitch is dead". (E. Hemingway)