I am doing a concours frame off correct restoration on the 70 monte carlo. As far as i know the headlight trim lower cast chrome was a early thing. Ill have to look at the headlight extensions that were on the car. There is a difference with the hole size for the 2 lower screws. Cast chrome bezels had a large screw hole. 70 montes that didnt get the lower chrome had small holes for the screws to go thru. I have both kinds here. some nos some used. Ill see if the car i am restoring has the non cast chrome headlight extensions. Hope this helps. It would be nice to hear some comments on this. I am new to this group. I started driving restoring 70 montes in 1980 till about 1995. Started back on them last year. I have a ton of parts as i never threw anything out. Thanks Brian