"FIT" is a loaded question. 1970, 1971, 1972 will bolt up with the correct frame brackets; However you would have to get the correct corresponding bumper trim rubber, hood trim, and headlight bezels and grill to match. The fenders themselves are physically the same, but the trim varies year to year, and (if I recall correctly) by style of car (GS hood molding is different from Skylark in some cases.)
not only is the hood molding different then the GS,the hood itself is different,the headlight bezels are the same,the bumper is the same,the grille is different also.Bruno.
Without changing other items on your car (i.e.: Grill,hood molding, headlight bezels, hood release latch system, ect ect) only 1970 bumbers will fit the front of your 1970 Skylark. If you find a complete rear bumper with taillights, frame brackets, ect... 1970,1971, & 1972 bumpers will bolt up and work on your car 1970 Skylark I have put other year bumpers on cars before its not hard you just have to do your homework and members here will help you.