Paola, for the trim plate codes:
TRIM 61 = Bedford Cord and Tan Leather
PAINT 14 = Sequoia Cream
See attached pages from the Buick Product Service Bulletins of 1948 giving dash colors for 1947 and 48 models. According to that source the dash, garnish moldings, instrument panel are painted the same color as the exterior. The mast jacket, directional signal housing, parking brake lever are painted Brown Metallichrome for your upholstery color.
To to get an idea of how the interior looked originally, try Googling some images of unrestored cars using the phrase "Buick convertible dash 1947".