Are all Dynaco PAS 3X's identified as such on back

I recently purchased what was listed as a 3X but it does not identify itself as such on the back of the unit. My friend has one that states 3X and I am wondering if any were produced that were not labeled as such. The tone controls feel like they have a slight detent in the center position and there are caps from the bass and treble controls ( both of which I have been told are indicative of it being a 3X.) can anybody shed any light on this for me?
Thanks, CK