I just completed a frame off restoration of a '50 3100. I replaced cowls, corners, etc. Yes, it is a lot of work, and yes, it is essential to test fit everything before final disassembly and paint. You would be amazed how things might have moved that you don't believed you even touched. With an AD truck every move of any part, cab, hood, doors, fenders, etc ... will effect the final fit. I reassembled and disassembled my truck numerous times before final paint and every time there was something to tweak. You do not want to find this out when everything is in final paint.
