Part number for 13,500 A/C for mini-lite 1905

[grwall]

We want to add the roof 13,500 BTU A/C to our Forest River Mini-Lite 1905. Normally it is an option for our unit, but we have to order it separately. Unfortunately our dealer doesn't seem to know how to do that. I would think that it would be a simple install since it replaces the roof vent and is supposed to be pre-set up for A/C

Any help is appreciated.