Part of our build process is to save the PDB files to a file share. This way we can debug the assemblies when needed. Without the correct PDB this is not possible, even with the sources available.
Visual Studio matches the assembly to the PDB with a GUID embedded in the files. Using dumpbin the GUID can be found for the assembly. Reading the GUID from the PDB file with a HEX editor is not so easy.
The CHKMATCH tool from debuginfo.com does the heavy lifting when checking for a match. Simply provide the assembly and the pdb file. The result is Matched or Unmatched (and the reason)