If you need every piece of inventory to have a unique, non-recurring number automatically assigned to it at the time or receipt, openERP does not have that.

openERP has fields called serial number and pack number, but those fields do not function in that way.

Pack numbers can be used, but it requires some heavy customization to get it to work as a unique, automatically assigned serial number for each product.

If anybody knows of a custom module that assigns a unique sequence number to each piece of inventory received, please chime in.