chrome fender and hood extension?70 dart

just wondering if the chrome you see on the edge of hoods an fender extensions on darts was an option? i always thought they were just on 71-72 darts but i juist saw a picture of a 70 340 swinger an it had em on there. i dont see a place to mount them on my 70, and ive seen several 70s w/o them. was it an option or is my car missing something?