Hi JereL,
You're asking for if-then logic which Provisioning does not currently have. It is a feature we are looking at introducing in LDMS 10 though.
That being said, you could theoretically write it into a batch file that does the if/else logic, and calls the script accordingly.
Example:
Create a batch file that will check if laptop or desktop, and from the results have it call the script of choice.
In provisioning copy the batch file from above to the client, and both laptop and desktop scripts (assuming you have one for each type).
Then call to run the batch from above and it will do the if/else logic and provided you scripted it correctly, it would call the corresponding scripts for if it was a desktop or laptop.