Hey, I also just picked up an Acro -- B/O badge, # 301 XXXX
The strainer and but plate are 7/8 tall, so post '77? The strained is the P-85, with the multiple holes for snare string...and in the Ludwig book, it says those were changed to 2 hole in 1980.
Serial number looks like it is post-79...so I have confusion. 1980?
Also, interesting thing -- the shell looked flawless, then I noticed a slight texture. The heads are very snug, and left small scratch marks - not in the shell, in the surface. It isn't powder-coating - too thin
My guess is that it was sprayed with some kind of clear enamel, or poly, or whatever.
Question: Will lacquer thinner, or acetone, or whatever works, harm the anodizing?
Third question: the lugs have little square indent on the top. I've never seen these. Some kind of special (or not) lugs? They are new to me.