Probably correct about the decal style indicating (approximate) year, but there are only 3 catalogs from PA on VeloBase, and these graphics don't seem to be in use either in the '84 catalog nor the '78-'80 catalogs. Those earlier frames look to be much more in the "Tom Ritchey" style and might even still be his hand-work, the "touring" model also came with 531 tubing. I would tend to agree with thinktubes that yours might be just a tick earlier than his '83/'84, but as you say the details are not "identical": not only the lug cutouts but also the chainstay bridge...otherwise, pretty dang close!