A few months ago, I purchased a 1963 parts car. It of course has round headlights (I have a 1964). I believe the covers are glass. Does any one know how I can tell for sure? They are heavy and sound like glass when 'thunked'. The markings say 63RQS. Additionally, there is a marking of a circle with two triangles, one inverted over the other. They are also marked 'L' and 'R'. I can't use them and plan to put them on e-bay so they can get to someone who needs them. I want to make sure that I list them correctly.