You have a Silver Streak. That is not the same as an Air Stream and this is an Air Stream forum.
So the best I can give is a guess. RV trailers of the era typically had solid axles with leaf springs. If that is the case using the axle as a lift point should work. Because it is not a torsion axle with a thinner tube for an axle that contains the springs. This is the reason for not lifting a trailer with a torsion axle. The axle tube walls are thin and contain the rubber torsion springs inside. Pinching the rubber spring rods from the outside of the axle tube reduces the suspension weight rating of the axle. A leaf spring axle .... totally different axle.
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!