I'm going with knock off...I hesitated for a second due to Usually the knock off T&Co do not have the little silver T disc by the clasp. It also looks lite weight for that style.
I've had the necklace and bracelet in that style and both have the slide bar through the loop closure instead of the lobster claw. I have a diamond cut T&Co bracelet with the lobster claw...I think it's either 7 or 9g. I don't remember.
I wouldn't pay more than scrap value if it's silver. JMO.
Kace