Are CUSIP identifiers case sensitive like RIC number are?
CUSIPs are not case sensitive.
Any letters within a CUSIP are upper case.
The CUSIP identifier was developed in 1967 by ABA and has not changed significantly.
The specification for CUSIP is detailed here: https://www.cusip.com/pdf/CUSIP_Intro_03.14.11.pdf This provides some further detail about how letters (instead of digits) are used, and mainly relate to debt securities and international issues.