There is no way possible to assign a part number automatically for a configuration / file unless you use any PDM / PLM System.
Or get an add-in custom scripted which can look up a database and assign the part numbers.
What is the Schema in your part numbers ? Do they have some info or mere running serial numbers ?
SolidWorks Enterprise PDM Would help you easily to assign part numbers ? Do you use SWEPDM ?
I've found a partial work around, I created an equation with the value I wanted, then I created a custom property, then assigned the equation to this custom property. I can then use the custom property in my title block. The downside is we will need to know all the equations we need to use upfront (which we do not).
We currently use PDW Workgroup, but are planning to get Enterprise next month. Will Enterprise let us create part/drawing numbers that are specific to equation values, and different configurations?
Could you share some examples how that equation should look like in your drawings ? and schema as well.
This would help me to understand better.