Your LP isn't chambered, but (as you've indicated in the title of the thread) it may well be weight relieved. Instead of large chambers like the pic above, the weight relief is basically just holes drilled most of the way through the body to remove some wood. Hidden, of course, by the maple top.
Chambering affects the tone, giving the guitar a semi-acoustic quality, but the weight relief holes don't have much effect because the "cavities" are too small to resonate.
I've read that most (maybe all?) newer, non-Custom Shop, LPs have 9 weight relief holes drilled in the body.
But yeah, it's more likely just a little bit of solder in the control cavity or something.