From what I remember, they were designed initially to a USMC specification but rejected (ed. just checking a lawsuit now - seems originally the spec was Army, but Gould Defense tried to revamp them for a Navy requirement.) They show up on Ebay from time-to-time but all are missing one component from the base, and three or four cards from inside. Currently (Feb 2017) there's a fellow with one on the armyradios group who's reverse-engineering the thing to try and bypass the missing cards. He's made some headway too.
The first one I saw on Ebay had a pic showing the missing r/t modules and it *looked* like they were at least the same form-factor if not the exact same crypto boards that go in to the slots in a KY-57 VINSON box. Since the KY-67 was supposed to incorporate the functionality of the KY-57 it wouldn't at all surprise me if they just used the off-the-shelf boards already in use in the KY-57 itself. At a guess.
(ed. I had a list of the missing transceiver internal boards - at least saved on my home computer as such - which reads as follows:
E-DTA: Audio and Interface Board 1A14 NSN 5810-01-048-8994 / 0N241639
E-DTB: CVSD Board (audio compression, I think) 1A15 NSN 5810-01-048-8516 / 0N241624
E-DTC: Clock Control Board 1A16 5810-01-048-8517 / 0N241626
E-DTD: ISSR Board 1A17 5810-01-048-8518 / 0N503181
E-DTE: Trans Alarm Board 1A18 5810-01-048-8515 / 0N241622
E-DTF: VPRC Board 1A19 5810-01-048-8516 / 0N241620
E-DTG: Input Recovery Board 1A20 E-DTG 5810-01-048-8513 / 0N241618
E-DTH: Power Supply Board 1A21 5810-01-048-8519 0N241635
...and running the NSN of one or two just now - seems the same as KY-57 - at least according to a publicly-accessible Navy doc.)