Minnesota Roof Snow Load Requirments

I own a park in southern Minnesota and time to time come across a good deal on a 90’s or 2000’s used home out of Iowa or another state. Minnesota is located in the 30 lb roof snow load zone but Iowa and other states are all 20 lb areas. I always ask the sellers of homes I come across if they have the homes data plate and what the load their roof is rated for on it but many, many sellers no longer have this document. Has any park owner in Minnesota ever brought in a home that was missing the data plate and therefor had an unknown roof snow load rating? I am missing out on a lot of deals.