MCW also publishes a handy book that lists auto colors by make, model, and year. It covers 1949 to 1978 (1929 for Ford). It cross references the MCW number to each color that they carry. This book is frequently out of stock so you have to keep your eyes open. Another handy feature is that the MCW bottle screws directly into my Paasche H airbrush.
MCW also carries factory colors in enamels but they need to be thinned.
I should also note that MCW recently moved from North Carolina to Ohio.