I know that striping a car is a lot of work, but, let me ask you a few questions.
How much money have you got in the engine?
How much are you spending on new body panels?
How much is the material going to cost?
How much more is it going to cost to strip the car?
You know where I'm going with this, I see it all to often where people spend a lot of money on other things and less on some things...now, I'm not going to say that if you don't strip the car that the paint job will fail...what I will say is that if the car is striped, you will know exactly what you have underneath...your call.
Oh, if the scrape along the side of the car isn't that bad, (less than 3/8 of an inch deep) filler should be fine...I hate saying that...I like to rough it our the best I can, is there any way you can get at it from the inside?