C.B.
First of all, do NOT judge by other children. My two year old can count to 20 and knows his ABCs, but still uses a bottle and doesn't want to potty train, and yet someone I know has a two year old who is completely potty trained, eats with a fork and spoon, but can't point to any part of her body. It's all about what the child decides is important. Give your son every chance to learn, but don't panic if he's not interested. Also, I know all parents revolt against using the television, but Elmo videos and the like REALLY help. My other son had developmental delays and needed therapy for much of it, but one of the things that he responded to was Elmo. There is a video about his hands, ears, and feet, and my son learned with that. There is a program, AZEIP (Arizona Early Intervention Program) if he truely is developmentally behind (they will do an assesment) that might help or point you in the right direction.
Oh - as per body parts in particular, not only Elmo, but playing "I'm gonna get your . . ." works well. Say "I'm going to get your" then pause and name a body part, like belly. After, blow rasberries on said bodypart. Sometimes, kids who seem not to know will giggle and cover the stated bodypart, showing that they just prefer not to point, but, if not, they'll learn through play.
Hope that all helped and was not too confusing! :)