I am rebuilding a 1969 Camaro. I had the body panel work done in a professional shop and they did a very good job on the seams higher on the body, they look very good. I guess the logic was to allign the more visiable areas and let the after market panel float at the bottom. This is good except for the 3" to 4" long seam, which completely laps but miss aligns in surface plain by about 1/4" to 3/8". I could put in a piece of small triangular sheet metal and tig this in then fill. But this would leave a small pocket under side to start rust it seams. Or should I just use a good filler. I am new at this even though I was just about raised in a body shop. I am finding naturally there are a lot of decisions to make that the color sanding and such as a kid gained me no hard knowledge of...LOL
Thanks for the help all,
Randy Man

Take it back to the shop and have them fix it if it was their screew up.
Otherwise if its lapped with a 1/4 gap you cant just put filler in it. filler is good for filling 1/8 inch. Anymore than that and it will end up cracking down the road.