Yes, this can be done. The middle section of my Extang Trifold 2.0 delaminated from the foam core, and started to bubble.
Contacted customer service and they were gracious enough to send me a replacement section.
Took around 2 hours to remove the defective section and add the new one. Amazingly it was only a few T20 torx screws, some engineuity, and 4 self tapping screws. Pretty easy!
Props to Extang for standing up for their customers and providing replacement parts for free!