Hi, I came across a Wilson PS 6.0 (85) .. It has the old PS6.0 cosmetic .... where the wording on the throat has only "Pro Staff" and no "Pro Staff6.0". The handle that connect the throat is slimmer than the current PS6.0. It's about the size of the PS6.1. On the butt cap, there is a "SDO" wording. I would like to know, is this a St.Vincent or something? Thank you.