"New for 2006-Cayuga Touring Kayaks" and they were "Variable Layer Polyethylene.
In the 2007 brochure, the Variable Layer is shown having and outer 'structural layer', then a center 'foam layer for buoyancy and stiffness', with a final 'Inner structural layer'.
As far as I can see in the literature I have, none of them were noted as 'PolyLink3' per say.
Hope this helps.
BTW, PolyLink3 is a tad heavier than what is used in the Cayuga line.
Kayak Carrier Kits
First Need Purifier