Sorry if this topic has been covered before. I'm still relatively new to the hobby.
The trucks on Lionel pre-war tinplate cars seem to have a tab that can be bent into a slot on the frame to prevent excessive rotation angles. Some of mine are bent in and some are not. This is a photo of two 654 Sunoco oil tank cars. The one of the left has been in my family since new. The one on the right was purchased recently.
Is this common? Were some forgotten during manufacturing? Or deliberately not bent in for a reason e.g. low-end 027 outfit?