My thanks to all who responded. The consensus is that bibs for no-longer-received serials are updated only if encountered during regular workflow. I appreciate everyone's help with this question.

Best regards,

***********************************************
* You are subscribed to the SERIALST listserv (Serials in Libraries discussion forum)
* To unsubscribe, send an email to the server address: LISTSERV@LIST.UVM.EDU . Do NOT include a subject line. Type as an email message these two words: SIGNOFF SERIALST
* For additional information, see SERIALST Scope, Purpose and Usage Guidelines.
***********************************************