I have an area of raised skin light brown in color and 1/4" in diameter overlapping my prostatectomy scar. Is it any reason for concern?

Have it checked. This sounds like a sebhorric keratosis. This is a non cancerous skin growth which is very common. However any new skin growth should be evaluated by your doctor to be sure.
Skin lesion. Although your description may possibly be a benign skin lesion such as seborrheic keratosis, skin tag, wart or dermatofibroma, it would be necessary to have a thorough history and physical exam maybe with a biopsy.