What were the cathode and coupling capacitor types that Marshall was using in the 78-80 amp?

[harddriver]

We all know that Marshall started using the chicklet caps green and red lego caps sometime yellowish in the 78,79, 80 models and this into the JCM800 years as well.

We all know the ole NOS Mustard cap was a metallized Polyester foil capacitor. What type of construction were these chicklet cap, I don't think I've ever heard this discussed.

Polyester, polypropylene???????