Not that I am a 'spert...but I do know where to find some additional info!
Check out the some of the catalogs, brochures & other information found here on the
VAC website. What you will find is that in the '40s & early '50s Airstreams were pretty much custom ordered with different interiors at the customer's request. The length determined the model, but within a model there were different options.
I concur, that what you have based on the VIN # is a '53 Clipper...pretty cool!
Shari