Modifying PDB files.

I am trying to solve a problem. We have been building and releasing
product without symbols files in general and what symbol files we do have
are DBG files not PDB. I would like to create PDB files for the release
version and store them in a symbol store. I assume it will take more than a
change of date to accomplish this task if it is possible. Is the
“signature” more than just the size and date?

Thanks,
Joe