You're right, I think, Keystone will most likely disavow any knowledge after the first year. Hopefully they can tell you what brand is installed, but knowing Keystone's record keeping..... <sigh>
The Dicor website is
www.dicor.com and there are links to the specific two Dicor roof membranes complete with warranty information, installation and maintenance links as well. The first link I posted was just one that referenced the membrane warranty information.
Here is the Dicor link to the membrane warranty that is on my trailer:
https://dicorproducts.com/catalog/ro...ubber-roofing/
It's interesting to note (I didn't know this) that the warranty is a pro-rated warranty. It is actually a 5 year replacement of materials (no labor or other equipment) and after that, it's pro-rated through the 12th year.
There is the usual "does not apply in some states where you may have more legal rights" so maybe, in the event of a roof failure, finding out where to file the claim may have benefit