This has been discussed quite a bit on the site, and there are a number of tests one can do to try and figure out whether you have pine resin in your slabs. The search bar with the right encouragement will yield plenty of info, but if you’re still having trouble:
That has been posted in at least 2 other threads.
Another one is to do a solubility test. Does it dissolve in alcohol? Does only some of it dissolve in alcohol? If any part of your product will not fall into solution, chances are very high (almost certain) that you have some bunk stuff on your hands.
TLC also likely won’t tell you about the pine resin content of the concentrate; it will only tell you how much of it is cannabinoids. Seems the BM has gotten wise enough to stop selling slabs of only pine resin. They mix it with distillate and sometimes terps too. I wouldn’t trust TLC to give the appropriate answer, unless that slab is 100% free of cannabinoids.