Get up real close to it and even use a magnifying glass on an edge of the striping. First you're looking for a raised edge, indicating that it is a vinyl decal and not paint (you can also of course tell this by hand.) What you're really looking for is a fillet of clear material (paint) from the decal to the body of the car. This would indicate that the body was re-cleared after the vinyl was applied - this basically extended the life of a vinyl from about 8-10 years to pretty much permanent. If this exists, then peeling the graphic will A) be difficult and B) possibly begin peeling the top layer of clear coat. This will required a dilligent wet-sanding/buffing job to feather the edge of the top clear coat. You wouldn't typically need a repaint because this is an extra layer of clear.
The last concern is that the paint under the graphic could be bright than the rest of the paint, due to fading over the years. The pigments on older cars are a little more vulnerable to this than today's cars. The only tip I can give is to maybe start at the back, bottom corner of the vinyl, and just peel up a tiny bit of the corner. Make sure the vinyl is warm to soften the adhesive. Use a mirror to reflect natural sunlight against the paint under this corner to detect any fading - a flaslight will affect your eyesight - natural sunlight is best. If you see fading, quickly reapply the vinyl and warm it back up to let the adhesive rebond.
If there's no clearcoat, and no fading, and it is indeed a vinyl, he should be perfectly fine to remove the graphics.
Sorry to be so detailed, but I would hate to see someone start something as simple as peeling a sticker off, and ending up with a huge mess on their hands!
Jeff
