70 Challenger rubber bumper fillers

[GoMangoBoys]

I visited the Edge car museum in Memphis yesterday.   They had a 70 challenger 426 Hemi car on display.   I noticed that the car was missing the rubber bumper fillers in the corners of the front bumper.  I pointed it out to the guy and he took me to see their mechanic.  The guy thinks that there might be a legit reason that they are missing.  Is there any variation or series of vin  numbers that would have no rubber bumper fillers?

[anlauto]

Yea, the same variation of VIN numbers that had red shaker bubbles 

[70/6chall]

These were both present on my 70 Challenger when I bought it. Noticed one day while washing it that one was no longer there. Guess they do fall out. Bought two repops at a Mopar swap.