interior paint texture?

[68blue]

Removed and stripped the dash and steering column and noticed that the paint has what feels like a fine internal texture in it. I am repainting these with the new color and was trying to decide on adding an internal texturing agent or maybe topcoating the new color with a softex clear.

I was really surprised at all the rust on the inside of the dash where there was no paint at all. Don't know if there was a reason for this  as it is my first restoration but I sanded and repainted the inside with satin black. Just didn't look right unpainted.