The ones that meet up to your bumpers, front and rear, are thicker than the rest.
I used an extra door moulding to make a moulding I needed for my passenger 1/4 front.
I don't know of anyone that makes the bumper matching mouldings.
I could probably help you out with that the next time I go out to my car. The SY owner has several '84 and before mustangs. That might be a week or so before I do though.
Send me a pm in about a week to remind me, i will forget otherwise.