Last year, I added 4 additional return ducts to my '12 RL ceiling as exact match to Redwood OEM grilles to help resolve the AC performance issue. I got them and other things from Tiara. They always ask me to take a picture of what I'm ordering and then they order them from Redwood.
On a recent order, I have found their Parts Dept. less helpful. I think it depends on who answers your phone call there. Stay on them - as they seem to be the only option for OEM components.
Mike & Pam '12 36RL, Kodiak Discs, 17.5" G114s H-Rated, SRE4000 w/HD Shackles, Joy Rider Shocks, Flex Air, 5.5 Onan, W&D, DW, 4 Scare Lights, (2) 6V Trojan T-145s; Progressive EMS-HW50C, Winegard DTV Sat, Sony/Denon 4K Home Theater, WiFiRanger EliteAC Pack, weBoost 4G-X Cell Booster.
2020 RAM 3500 Limited CC, LB, 4x4, DRW, Cummins HO, AISIN, 4.10, Curt A30 w/OEM Prep, Transfer Flow 70gal Aux Tank/Toolbox.