That is an interesting one. I would say it was coach built. Is the front clip with it? I would jump on that in a second. The cab might be a little small inside judging by the size of the back door but it is hard to tell from the picture. From My research, there is only 1 LCF crew cab made by GM. It was a 1956 GMC. I talked to the owner when he was selling it and he had documentation form GM. It was made for the District of Columbia public libray and had a moble library trialer that GM also made. It was a 3 door.
Here are the pics of it
http://s1356.photobucket.com/user/buggy5872/slideshow/book%20mobile
