Do Smart Licensing Request Codes expire?

[RB6502]

I'm working with a customer where we generated a bunch of C9500 license request codes over a year ago (at the time the equipment was installed).  The customer never got around to completing the process through the licensing portal, but they will hopefully be doing this soon.  My question is can they still use the request codes that we generated for them last year to generate the license tokens, or do we have to generate  new request code on each switch?

[Flavio Miranda]

Hi

 I could not find a doc stating that this information expires.However, this information must not change as the device should be uniquelly identified. As you can see, the serial number of the switch was used as part of the code.

# license smart reservation request local
Enter this request code in the Cisco Smart Software Manager portal:
CK-ZWS-C3850-24P:FCW1831C1A2-BgPWudjgx-50