I have an 18 yo Trav'ler satellite auto search dish using DTV and it's worked fine now for 3 years.
What I did when I first bought this RV, since there wasn't any receiver with mine either, was to look on the dish as it was trying to extend...it'll do that w/o a receiver, and yours you'd just crank up. And there in the middle of the dish, is the name of the provider. DTV, Dish, or that Canadian outfit. Blue something.
Armed with that info, I called up DTV and had a receiver in my hands in 2 days.
For your other dome, I'd suspect there's something on the dome itself that will identify the satellite outfit. Send some young kid up there to find it.