Hi Stevea,
Hopefully your door just needs a little latch adjustment. A copy of the shop manual may be of some help and could be a very good investment. Also available on line.
http://chevy.oldcarmanualproject.com/shop/1955truck2/index.htm If it's a little more complicated just ask.
In Portland there are a few other vendors I have heard of. Cliff's gets up to Seattle swap meets a lot
http://www.cliffsclassicchevrolet.net/index.html I haven't done business with him but in talking he seems like a pretty stand up guy. A company called Dan's
http://www.dansclassic.com/index.cfm is also in Portland.
Is Seattle out of your way? We have a few good contacts here too. Do you know about the Portland Swap Meet?
http://www.portlandraceway.com/index.php?option=com_content&task=view&id=42&Itemid=107 It is legendary.