Need to find out if my rear brakes (Drum) have ABS Speed sensors.

Model is LT extended cab with V8 5.3 w/flex fuel. Front brakes are disc. Reason for question is my ABS light along with brake system warning light and chime came on. This happened a week after I had new front and rear brakes installed. I returned to Pepboys and they checked the error code. Error code states there is a malfunction with the left rear abs wheel speed sensor. However the Pepboys tech states there is no rear sensors on my vehicle. I need to take it to a Chevy dealer to trouble shoot the problem. I need to know if there are no rear speed sensors. Thank you for your assistance.