I know of no front wheel drive 31' motorhomes. Perhaps in Europe some of the small Class C's and Super Bs. But I can't think of any in the US - ever.
You can get down and look under the coach at the 25' drive shaft from the transmission to the rear differential to confirm for yourself.
Since there are no front drive motorhomes there would not be a need to put that info in a brochure or owners manual or anywhere else. It's assumed.
2017 Winnebago Adventurer 37F
2016 Lincoln MKX Toad