I'm not well versed in Peterson nomenclature, other than to determine a pre-Republic pipe. This cased, two-pipe set is stamped "Special". I can't find out anything on this grade. Even if the Special stamping isn't significant, I think someone did well getting two pre-Republic pipes for under $150/pipe.
http://www.ebay.com/itm/2-PETERSON-039-S-SPECIAL-Briar-Pipes-w-Red-Case-Pre-Republic-Ireland-Excellent-/221522539391?autorefresh=true&ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2047675.l2557&nma=true&si=k0MKj6Wu%252FW9hGoxfEOVfjxMo1wE%253D&orig_cvip=true&rt=nc
http://www.ebay.com/itm/2-PETERSON-039-S-SPECIAL-Briar-Pipes-w-Red-Case-Pre-Republic-Ireland-Excellent-/221522539391?autorefresh=true&ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2047675.l2557&nma=true&si=k0MKj6Wu%252FW9hGoxfEOVfjxMo1wE%253D&orig_cvip=true&rt=nc