70 Shasta Where Might I Find The VIN Number On A Mid 70's Model Shasta Travel Trailer?

Where might I find the VIN number on a mid 70's model Shasta travel trailer? - 70 shasta

I need the VIN number on one half of the model Shasta trailer 70 to be found to have received them. Bought to make the man, the trailer could not find the previous record for a purchase, you will need the VIN number, we were not able to you who may locate.Thank help.RD