What color primer was used

Hi guys and gals

Happy new year to all my FABO friends.

I seen something strange on my 1972 Demon as I was sanding down the paint to repair some dents. The car was a yellow when I got the car repainted with a cheap paint job. Here is what I found, as I sanded thru the yellow paint I found what looked like grey primer and than red primer under that. Was this normal from the factory.

It just seems strange to me as I have always found only red primer under the paint.

Rick