1 repoduction the other ??????

now i know the one on the right is a reproduction but the one on the left i am not sure? i looked at a couple on Ebay that match the left one they say its from 1974. here is what makes me wounder, where the metal wraps around the edge and the trim that meets the glass is a rolled under seam on the ebay one and my repo! where the my other one it has no seam or hem its just flat 1 layer, if that makes any sense? then theres a couple other little things like theres no plastic film on mine and it dos not have the small fine print on the edge like the ebay and my repo one has. and maybe it is just a printing error but where it says REG US PAT OFF on the other 2, my other one says DEG or OEG US PAT OFF . maybe im grasping at straws? if anybody has any idea i would love your opinion! i have had these for around 5 years and always wondered, thanks