The Hideout 28BHS is an aluminum skinned trailer with aluminum front/rear panels, so delamination won't occur. Delamination is water damage, usually to fiberglass panels.
Your example is a 2016 "used" trailer. If you could talk to the previous owner you might gain some insight into how it was used, why it was traded, etc. Paying $21,000 seems relatively high, given the internet offerings for a 2018 model of $22,499 with no negotiations being done.
https://rv.campingworld.com/rvdetail...20k-HAR1468718
It may be a "good deal" depending on the condition of the trailer, how well it fits your family needs and what kind of dealer support you can expect after the sale. Remember, for most people who need dealer repairs after the sale, the dealership becomes a major consideration in purchase location, many times it's more important than the final price. For people who never return to the dealership, price is more important than dealer support. Which will your purchase be? It's impossible to know before you tow it off the lot, so be sure the dealership is one you can rely on. If there's "independent technicians" roaming the lot, I'd wonder why ???????