Sorry, I can't help with a spare K-1 relay, however as I am trying to repair three of these power supplies, it might be worth posting a note on them to see if you (or anyone else) has any clue as to why they do not appear to be built to drawing. You may need to sort this out before you can obtain the correct part.
What I note is that the manual TM11-983 shows K-1 relay as having 8 pins (in both the circuits and the photos of the chassis underside) and relay A with one changeover contact. And yet when I look at the actual relays they all have 9 pins, and relay A has a second contact which switches pin 9 to ground when the relay is energised.
Furthermore, transformer T-1 has 22 pins in the manual, but only 18 in my three samples.
I wondered if the suffix on the type number "PP-114" has any significance - I have one "PP-114A" and two "PP-114B". They appear to be identical in the above respects. You had better determine which variety of K-1 relay it is you are after - no doubt the later type will fit the earlier PSU, but not vice versa.
Anyone know if there was an updated manual for this PSU?