LPC publishes a pamphlet with specific guidelines which cover 'finish' which
in their definition also includes color.  Although they state that the finish
(ie color) should match, they can be lenient, especially if the color is
chosen from B.Moore's "historic color series"-

they are more fixated on buildings that are prominent features.  There was a
story going around which I don't know how true it is, told to me by the
window installer on the Empire State Building that the original windows were
never intended to be that red color.  They were shipped with a metal primer
and were never top coated.  As a result, when eventually painted, they were
painted red as it was assumed this was design intent.  LPC insisted on red
replacement windows.

This is similar to the Giraffe story I intended to tell Ken's wife 2 years
ago.

Anni