Can't tell by looking but most rv trailers back then were seamless aluminum material. I would have a rv tech tell you what the roof cover is and what type of roof coating has been used on it and what options you have.
One picture looks like the trailer is a flat roof also normal back then. Those old flat roofers left puddles or lakes out in the center.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers
'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 two slides