They are (besides the Monotron Duo, which has a second oscillator (but no way to play it paraphonically without hardware hacking, you can just tune it differently)), but this is the Monotron Delay, which has, well, you can probably figure that out.
What I'd love to see is if they could use the same tuning system they used here to tune the delay time and make the monotron delay do some kind of karplus strong synthesis! That's assuming there are patch points for the delay time, I guess...
you can accomplish this by automating VR6A on pin 6 of the pt2399. one oldschool method to add CV control of a potentiometer is to control the resistance with a vactrol.