For what is worth whenever I play a tiefling they tend to be descendants of beshaba, so they definitely have antlers.

Quote Originally Posted by Races of Faerun
Some tieflings were not descended from mere fiends at all, but from powerful gods. These tieflings often had their own physical characteristics that set them apart. Tieflings sired by Beshaba, for instance, often had antlers instead of horns and pale, white hair.