You can find data plate info on the internet by “googling” the make and year and data plate info. For your ’59 I got the information from the Spring 2001 issue of Quicksilver. Trim code 326 is medium blue metallic vinyl and medium blue box weave cloth. There are also trim codes 326A through 326D listed with minor differences in the material used but all medium blue metallic.
Also, if you get a shop manual for your car they usually have data plate decode information in them as well.