Your .38 Special was made sometime around the 1978-79 time frame. It should be a Model 10 or 12 based upon your serial number and description. A 3-inch barrel would be scarce. Measure the barrel from the forward end of the cylinder to the muzzle.
Your .38 should be a fixed-site model. You can find the exact model number by opening the cylinder and inspecting the cutout behind the cylinder arm. You should see a stamping like "Mod 10-5" or similar marking.
Depending on the region of the U.S. these revolvers, in excellent condition with no scratches or dings, can fetch anywere from $275 to $399, with about $300-$325 being average in my experience. Your 3-inch barrel would probably add another $75 to that price.