I have CA ASM2 on my mainframe, but I don't know what release I'm running.
CA ASM2 is installed under SMP/E.
If you have FMID CNU4200 you have release 4.2.
If you have FMID CNU4100 you have release 4.1.
Another method to review, assuming you installed a new SAMPJCL when you installed Release 4.1 and 4.2, is to look for the following member in SAMPJCL:
CURRENT CA-ASM2 GEN LEVEL = 0211L142
TAPE = L10211
0211L142 denotes BASE Release 4.2
L10211 is the tape label that was used when you installed CA ASM2.
Support for CA-ASM2 Release 4.1 was discontinued 12/31/2004.