Define 1956/B red leatherette interior

[Jerrold Marsala]

Fellow Porsche enthusiast,
I have a 57 coupe per COA body #57913, made 11/15/56.
The exterior paint code is black/5601.
The interior material is red leatherette/B
Any original owners of a similar car with the /B
out there who can help me? Is it possible that my 57 was made with 56 options? This would appear to be why I'm having problems as it fits the criteria of the 56 model more than
the 57.
On tearing down the vehicle, I found:
black exterior, red painted garnish rails, red dash cap on a black dash, red seats, black side panels and
black/charcoal rugs
Here's my problem, 57 cars are listed with an option for a B interior/ differs
from 56 B. What the hell does the B stand for? What are my options in carpets,
side panels, and door panels? Does anyone out there have an original 1956/B who can
help me?
Dr. B. Johnson's book states that the 1956 356 A Porsche with the 5601 (B) Reutter #701 with a beige dash/black upholstery (does this refer to the side panels?)
As you can see, I'm totally confused.
Jerry Marsala
56 speed
57 coupe
(both basket cases-same as me)