How to determine if a ZPL II label has been produced based on the requested DPI

Overview
I need to verify that the label I have requested when also submitting the specific DPI, has returned a label in the same DPI.

So for example:
I want a label which is 300dpi. I send my request and the code for the ZPL II is returned. How can I now verify that this code for the label is for a 300 dpi label please?