I have both styles of 215. I wonder why some had the stamped number and some didnt?

I need to do my 68 HEMI RR auto, and then my 69 HEMI Charger 4 speed. I was thinking Id use the 215 fans I have on those cars, and then the other 216 fans I have on my E Bodies.

Also, i guess all 216 fans had the inked number?