Have you been able to figure out what OS the Trailblazer currently has? I'm brand new here but was able to find my pcm's OS by reading my PCM with an OBDlink LX and LS Droid which is an android app. I believe the same can be done using PCM Hammer. Once you have the number to your OS, then you can search for the proper XDF file to work with your bin. LS Droid and PCM hammer can also output your stock bin file that you can edit and reflash to the pcm.

From what I gathered there's no way of knowing what OS is on your PCM by looking at any of the labels on it, it needs to be read by PCM Hammer, LS Droid or similar app.

If it's the stock pcm then I believe you can follow the below steps (believe because I'm brand new myself)
step 1: figure out what OS is on your PCM using LS droid or PCM Hammer
step 2: read and save your stock/current bin file
step 3: find a xdf that matches your OS #
step 4: load the matching xdf and bin files into Tunerpro to make changes to the bin