As mentioned in other topics the 33 factory calibration constants in a CSA803A/B/C (and corresponding 11800 models) can be set, but not read, in U500/U511 using the GPIB command calcorrection. These constants get lost and replaced by zeros after severe T1331 error problems and "Dallas" battery replacement. When the constants addresses are known the NVRAM images could reveal whether a CSA likely still has its original calibration constants (not all zero).
In my CSA the addresses are, in sequence,
U511:784F, U500:7850, U511:7850, U500:7851, U511:7851, ... , U500:785F, U511:785F.
Time base firmware 4.01 .
I speculate that these "constants" get never changed (from zero for instance) by ordinary accuracy commands. I haven't checked that (yet).