Typical and accepted iconography. Right-hand index finger pointing up and a cup in his left hand. And mirth in the stance. For more details please see another blog on Sambandar on this site.
Sambandar is s depicted here as a child, naked but for his ornaments. Despite being portrayed in his childhood he has the body of a teenager, fit and toned. See his back.
His ornaments include earrings, neckwear, armbands, waistband, wristbands and anklets. He is standing on an inverted lotus pedestal and the pose is Tribanga.
This looks to have been cast as you see it. A real class and a delight.
The bronze is about 6.5 cm in height. The seller, an auction house, had estimated it to be from the sixteenth century. I do not have any better estimate. This is from Tamil Nadu.