Yes, must be on land and never moved since placed there new. Also hitches and axles removed, and ideally a perimeter foundation such as brick skirting.
I don't deal in government backed loans, but I thought - with one exception - that the home had to be on a permanent foundation and attached to the land with the land in the deal. The exception is that 21st Mortgage has a government backed Title I program available to them that they do not use much.