It is NOT an M105. That is very clear from the data plate photo in your first post. An M105 would have a gross weigth over 7000 pounds and uses either 11.00x20 or 9.00x20 tires, depending on configuration. Your data plate shows gross weight of 2950 and 9.00x16 tires, which means it is an M101, not even close to enough capacity to be an M105. Also, the sidewall bracing is not heavy enough and the frame rails are not large enough to be an M105, and the tongue support leg is distinctively M101.