Q. Our libraries rely on OCLC numbers as a shorthand to differentiate between bibliographic records, what will that look like in Koha? Is there a best practice around what part of a bib record is used to track and identify different records?

According to Ann, who is a member of the Koha Cataloging Interest Group:

"The Koha record number is the ‘linking point’ between bibliographic and item records.

This is a running number which is automatically assigned as a bibliographic record is created in Koha (i.e. in your Koha database) – whether imported, or created from scratch.

Note: Your Koha number will be different to ‘my’ Koha database number, even if we’ve both copy catalogued the same record from OCLC.

This is functionally identical to the OCLC number – which does exactly the same thing in OCLC."