Sebo,
Most of my really old (1975-79) monokote saw stored in a garage (exposed to the element) or in a attic. In both location I found a few roll were the adhesive dried out. I pretty sure if I used Balsarite I can still use the stuff. The stuff stored in a dark dry basement or in the house is still good but the adhesive has degraded some.

The only Coverite I've ever used was the old Super Coverite iron on fabric and the old their old iron on silkpan stuff, both you had to paint. Almost bought some of their iron film when they first came out with it but I didn't like the feel of it back then. Got into control line/RC 1974. Plastic models at age 6.