Yes, Pecaco decks are unique, similar only to St. Louis Meramec with deck-wale scarfs in opposite directions (St. Louis also founded, later, by Wickett). But those Pecaco and St. Louis catalogs can be confusing. In the 1917 and 1920 Pecaco catalogs (see
http://merchandise.wcha.org/index.php?cPath=90_91), all the photos of canoes on the water show courting canoes. This was always confusing. I wondered if Pecaco simply added pretty pictures to their catalog regardless of whether the canoes were theirs. This is likely true- one of the same photos from these catalogs turns up in the 1925 St. Louis Meramec catalog (see attached). Apparently these fine people were lazily enjoying the Meramec River- which flows out of the Missouri Ozarks toward St. Louis and the Mississippi- long before Wickett ever moved to Missouri! To be fair, Pecaco did offer long decks (see page 19 from the 1917 catalog below), so perhaps they made some courting canoes.
No matter what, the features of the canoe in question together with the on-water catalog photos suggest that there may have been some connection between Wickett and the Boston market (maybe via Robertson?). Perhaps Wicket was "courting" the Charles River market, but that alone cannot explain details like the planking being let into the gunwales and stems- no one would ever see such a detail. On the other side of the coin re this particular canoe, note one feature more typical of Maine than Boston- tapered ribs. Most of the Charles River-area canoe makers (Robertson, Waltham, Nutting, Arnold, for example) did not taper ribs, but rather left them full width to the gunwale.
Re open vs. closed gunwales: cuts of decks showing the Pecaco arrowhead always show open gunwale, so I naively assumed that they only made open gunwales (and the ones I have seen were open gunwale). But...reading on... the catalog in several places makes reference to open gunwales costing extra (see page 11 from the 1917 catalog below) except in the Notacrack model which was open gunwale only. This was around that transition time when other builders were offering open gunwales at higher prices.