There were other plastic-coated paper caps, without stripes, that are just as unreliable as bumblebees. The pink caps in this photo are examples:
They can also be in black cylinders with printed values rather than stripes, etc.
Another type of plastic-coated paper cap is flat and rectangular, similar to this:
Some people call those "micamolds" after that company's name, but they were also made by Solar and other companies.
All of those caps use paper inside and they are just as bad as wax paper caps. No need to test them unless you are curious -- they are garbage inside, even if the plastic case is still shiny and new-looking.
I'd guess that in a 1964 set, "drop" type caps -- similar to orange drops, but they can be colored maroon, brown, blue, green, etc. -- are iffy. In my 1961 RCA CTC-11s, both sets worked, kinda, sort of, with the old "drops" in place, but they didn't work well until I replaced them. With all of the original drops in place, my 1958 CTC-7 showed a weak picture with bad vertical & horizontal sweep and little or no color.
The more maroon drops I replaced, the better it looked, until I got this:
If you want a cap checker, you must get one that can apply the cap's actual working voltage (i.e., don't rely on a modern handheld meter). Here's one that I use:
There are other brands & models; I also have an EICO 950B. Any vintage cap checker will need restoration, like a radio or TV of the same age. I use mine mainly to test mica caps. I don't test paper caps, for the same reason that I don't check the air pressure on a tire that's obviously flat. Maroon drops . . . maybe, although I can replace one in about the same time it takes to haul out a tester and check it.
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html