Stripping them is a good idea.

At Sean Malloy suggestion I took off the goopy thick red primer to find what?

Rust of course.

Either moisture soaked through the primer, or it had a bit of surface rust on it before painting... who knows? But its got it now and i'm glad I took it off.

Who wants to install new rust on the car anyway.
Might not be compatible with the old rust.

Primer is pretty much useless as a rust preventative. After shooting primer, the cover with paint time is usually 48-72 hours before the primer starts to get porous, which lets moister in to start the rust.

So striping the old primer off before painting is a great idea if you want your paint job to last and not lift. I've refinished paint on cars and bikes where the primer was not stripped and the paint lifted enough you could pull the paint off in strips, and it always separated at the primer/paint boundary.

Good paint is 90-95% prep, the shooting of the paint is the easy part.

Good Luck, Don