I think that Cisco's SNMP team is sometimes overmedicated, or maybe just itinerant, or the 1st to get laid off when the Wall Street quarterly statistics dip.
For 2960's we get Machine Type of just Cisco. But there's another field in Physical Entities that I found in Report Mangler called simply, Model, that shows the full WS-C2960-24TC-L. On the other hand, that Model field is blank for 2951 Motherboards - unlike any other device. Sheesh.
Plus the inventory reports are not properly sortable by model because of these Cisco inconsistencies.
But enough about me and my peeve menagerie.
When you say NPM, which NPM screen, window, alert, event, or report do you mean?