I didn't get a choice... Only some of them specify I think. The schoenorchis said it was mounted but some of the others were a surprise. I ordered a sophronitis, neofinetia, haraella, two restrepias and the schoenorchis and only the soph and neo were potted... Might be worth mailing them with ones you want and seeing if they have a choice?
I don't usually like mounts either but as these were minis and for a live planted reptile tank it suited me at the time!
Nice to see there's another reptile keeper on the board. I keep mainly terrestrial pit vipers and monitor lizards, so not much chance to do elaborate planted set-ups with those, but I have some rear-fanged arboreals in planted viv's.