My 2 cents worth.If it is on a 55 2nd series it is like my 57. Don't do it.The roof spot welds to the cab in that gutter. You grind it off and you will end up with a 55 Chev truck convertable. Most vehicles,if not all, you have to take the roof off to replace the rain gutter/rail, so I would repair it as best you can or leave it alone. It just depends on how far you want to go with your trucks appearance. I am replacing my roof, but I have replaced roofs before so I know what I am getting into.

1957 Chevrolet 1/2-ton Stepside LB in the Gallery
My Photobucket shots

The person who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself." - John Stuart Mill (1806 - 1873)