Detail of an F-1 engine nozzle extension being
stored in the west parking lot; the nozzle extensions were removed from the S-IC
I didn't notice this at the time I took the picture (otherwise I would have
taken a lot more pictures), but it appears that the trailer behind
the nozzle extension is holding at least one, and perhaps two, Instrument
Now, the USSRC has always displayed a fully-restored IU, but a second IU
would be prepared for display with the Saturn V in the Davidson
Center. While the IU was being restored, a fire broke
out in the restoration facility, although as it turns out no important
artifacts were severely damaged.
In the above-linked forum thread, someone mentioned that the USSRC had two IUs
that they had been storing in a back lot, so these may be those IUs.