Yes, it doesn't hurt to try. I bought a GP Spirit Elite Kit this weekend and all of the plywood in the kit was deformed. I emailed GP directly last night and they are shipping me the replacements.

Always ask, it never hurts. If Horizon can't/won't help, then you have 2 options, you can either wait for the shop to come back from vacation, or order something that would be a suitable replacement. But I do highly recommend contacting Horizon first.