[Milsurplus] URR-21 Crystals ?

[Hue Miller]

I found one of those crystal boxes for the URR-12 receiver.
The crystals are FT-243 in marked freqs 14.23 to 18.21 MHz.
My question is, these are probably not fundamental, right?
The only way I think I could determine this would be to use
one of those small crystal checker oscillators together with
a frequency counter. No - wait - a signal generator and 
diode pickoff would show the parallel resonance, which
unlike the series resonance, does not repeat at (odd)
multiples.
-Hue Miller