pF values do come in box film cap form factors, and for sure there is a pF cap there (just check out almost every single OD circuit out there, between pins 1 & 2, etc)
I do recall this cap and the material do matter, but I'm not 100%. At least an example would be to use ceramic caps in the power section vs film in any given circuit, since the ceramic helps with high freq. Oscillation/noise.