I don't know of any Keystone product that has a polycarbonate front cap.
There are several changes that have occurred through the years with Keystone products with fiberglass sidewalls and a fiberglass front cap.
First was a "wrapped FILON front sheet" as is still used on a number of trailer brands.
Next came the fiberglass MOLDED front cap. Initially it was white and matched the FILON siding. Some had a gelcoat finish, some didn't. Those without usually pitted in a couple of years.
Next came that same fiberglass MOLDED front cap with color added to the fiberglass resin. With them, some had gelcoat, some didn't. Pitting was accompanied with significant fading of the color.
Next came "spray painted fiberglass MOLDED front caps with a gelcoat finish. They seem to have become the "upper grade standard build" and have, for the most part, eliminated the issues with fading and pitting of the front cap.
As for polycarbonate, SOME newer trailers from Keystone have a polycarbonate window in the front cap, but I don't know of any brand produced by Keystone that has a "true polycarbonate cap".
In 2013, Cougar was installing fiberglass MOLDED front caps. I believe (If I remember correctly) they didn't start the automotive paint finish until 2015 on the Cougar line. The gelcoat finish was applied to 2013 and 2014 models over the "white fiberglass" while the 2015's were painted over the white fiberglass. There's no polycarbonate caps on any Cougar that I'm aware of.
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS