I grabbed them a little differently, but to the same result. I wrote a SQL query that copies from the Custom Poller Status table to my Nodes table in a customproperty field:
SET SerialNumber = s.Status
FROM CustomPollerAssignment a JOIN CustomPollerStatus s ON a.CustomPollerAssignmentID=s.CustomPollerAssignmentID
JOIN Nodes n ON a.NodeID=n.NodeID
WHERE a.AssignmentName like 'CiscoSerialNum%' AND s.Status !=''
This implies CiscoSerialNum is the assingment name (name of poller) and SerialNumber is the field name in Nodes table.
This will probably work in your environment, tweaking the two above field names, but as always, before doing any DB tweaking, DO A BACKUP of your DB!!!
Hope this helps.