I'm quite sure that it started out being a Chev. It has exactly the same crossmember as the picture red58 posted. I have several 55 GMC's which use a different crossmember and a 59 with another crossmember yet. I have seen pictures of fleet option GMC's but never recall seeing one in its time. We had a very strong GMC dealer here right after WWII and he sold a lot of pickups. Then came the drought of the 50's and very few pickups of any kind were sold in this area. The GMC dealer died young of cancer and when the drought broke, there was a very aggressive Chev dealer here. Very few mid 50's GMC's were sold around here.
