<VV> Horizontal Paint Runs?

[par429 at aol.com]

OK, so what's the deal with this?  My current project car ('69 500 
coupe) is pretty much a shell on jackstands in my garage.  I'm working 
on cleaning/sanding the engine compartment.  Inside both rear quarters, 
like behind the battery or spare tire, are runs in the black paint that 
are horizontal and run toward the front.   It looks like the car was 
hung by the rear bumper when it was painted.  Did the factory do this?

Can anyone offer an explanation?

Just  curious.
Phil
3 '69's