I checked with beta tools and cannot find a way to create a new O-chit and put it on the spiral or in the Reserve Pool. Possibly someone knows how to edit the game file to do it, but I don't.
However, I do see a US O-chit in the "Removed Pool". (You can only see this pool with beta tools.) This would seem to indicate that you have built two of them before now, if one has gone missing. Either that, or the one you recall was built and it got used for something.
it is easy, move though the turns, and see if the one in production is added.
the wif rulebook is my bible
I work hard, not smart.
beta tester and Mwif expert