Sstock
I am also doing a restoration of a 1953 five-window truck. My truck exterior will be the original Mariner Blue. The correct color for the interior for all 1947-1953 is a low gloss hue of metallic brown called "champaign". I purchased mine pre-mixed from Classic Parts, item #31-014 (Interior Cab Paint Champaign $49.95 per qt.) The color is close but finish is very low gloss.
I have a section of an original 1953 seat cover and it is a dark brownish-maroon with a grain texture. I purchased the Spanish grain maroon seat cover sold by Jim Carter (#UP109) and the color and grain is a close match to my original cover section.
Don/RdsLessTaken

Interior Color:
http://i1291.photobucket.com/albums/b542/RdLessTaken/1953Chevy5_zps263e1165.jpg
http://i1291.photobucket.com/albums/b542/RdLessTaken/IMG_00675_zpsbb0d9feb.jpg

Seat Cover, Door Panels, Arm Rests:
http://i1291.photobucket.com/albums/b542/RdLessTaken/IMG_82895_zps56117817.jpg