70 Chevelle master cylinder appearance

A 70 Chevelle built in late November 69 will have ????? a rectangle reservoir master cyl. or the rounded contour reservoir type ????? What is the opinion for my restoration? It is F41, disc brake, original big block equipped. I want only original appearance. Appreciate some help.

[SS427]

Michael,
The master cylinder is part number 5470409 with a 'BB' stamping on the front pad, rectangular with bleeders and a single bail wire. It is always a debate but it should be natural finish with a slight spraying of semi gloss black excluding all machined surfaces.
Rick