How to Tell If Post is Being Boosted

Hey guys! I check my competitors ads on FB and they have no dark post. They do have a lot of engagement and shares. How can I tell if they are boosting the post? Is there a way to see if they are boosting friends of friends or detailed targeting.

Thanks

Also interested. I have a good idea of how to guess, but it's just that, a guess. Engagement differs, so the only way to guess accurately via my method is if both pages are promoting almost exactly the same content, and neither have fake likes.