Wellll.... there has to be a common theme amongst them.

We all know the point of assembly is the same for all Crossfires, so we can rule that out.

So, my next things to ask would be:

-- Is it specific to Coupes or Roadsters?
-- Is there a year in which is does not appear?
-- What's the lowest known VIN of the vehicles including the reduced storage size?
-- Are they all Limited trim?
-- Does it affect both US and International owners?

As we all know, there weren't two generations of Crossfires. If the stamping on the bottom of the "blanker panel" is A 193 XXX XX XX then we know it's specific to the Crossfire (not leftovers from the R170 SLK, which would be A 170 XXX XX XX). If it's an A 170 part number, then we can do a search and probably find the guy

See if you can find out "common ground" among them. The absolute LAST thing any manufacturer wants (from a quality/warranty perspective) is a completely randomized installation of different design levels of parts. In the case of trim, it's bad enough -- but imagine if this was a structural metal component? This could (and has, at Nissan) cause the assembly line to scrap the entire BIW because of mis-manufactured sub-assemblies.

So... even though it's not glaringly obvious now, there MUST be a reason for its existence.

Maybe ask one of them to disassemble that back portion, and take a peek? It's an easy area to inspect