I suspect are vinyl-covered aluminum. I'm pretty sure that is what Old Town uses on the Royalex Penobscot and if you go to their site and look at the pictures of the Penobscot 16, that is what the gunwales pictured look to be.
Someone who doesn't know a whole lot about canoes might not realize that there is aluminum underneath the vinyl.
if there are surface scratches taking off the outer finish, and you can see tan under it, it is royalex.
If there are scratches and all you see is the same color, no matter how deep they are, then it is poly.
Digging through the old catalogs, it looks as if Old Town turned the Poly Allagash into the Penobscot 164 sometime after 2004. (Must have been inspired by Mad River turning everything they made into Explorers.) The Allagash/Penobscot 164 is several inches wider than the Penobscot (37.5" vs 34"), so that’s something which could be checked pretty easily. And for what it’s worth, at least as recently as 2000 the catalog did say the Penobscot 16 was available in optional wood or vinyl trim. Since this one seems to be a 2003 model it looks like a pretty safe bet it’s the real thing.