Polypitch electronic instruments

Hi everyone,
I am a just intonation composer and have been using MuseScore for quite some time to create just intonation music (using its tuning option accurate to a hundredth of a cent) and I'm loving it so far.
Since I also often make use of electronic instruments, including some from the MuseScore soundfont and some from other soundfonts, I'm curious about one detail: I'm aware that many instruments have clearly audible harmonics, and I can easily discern that they are acoustic harmonics (in natural number ratios above the fundamental).
But what about inharmonic polypitch instruments, which contain additional pitches that are not harmonics of the fundamental (Soundtrack, 5th Saw Wave, and Crystal are examples from the MuseScore soundfont)? Are these fifths and fourths equal-tempered or just? I can't tell by ear (as far as I know, there are none with intervals from the fundamental further away than 2 fifths), and I wonder if anyone who knows these instruments a little better could tell me.