dsc11162.jpg

Detail of an F-1 engine nozzle extension being stored in the west parking lot; the nozzle extensions were removed from the S-IC in June.

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 Units.

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.