rear defoggers

Hi.

I have gathered the parts to install a rear window defogger in my 69 notchback. The bezel that goes on the rear shelf has a slight curve to it. Is this correct for 1969. A friend of mine has a 1970 Swinger and his bezel is straight. Did they change in 1970 or were they all straight. Anyone know which is the right one for my car. Thanks Bobby