Identify original headlight reflectors?

[jimmyz80]

What's an easy way to tell whether I have original reflectors, or repros? I'm guessing they are original, since the finish is very poor, and there is some sort of reflective plastic insert that is sitting in front of them. Was it common during 1970s restorations to put some sort of reflective insert into the headlights, instead of re-silvering?

The reason I ask, is I'd like to get the reflectors re-silvered, but only if they are original.