Supraphonic
From 1961 until 1968 the interiors were painted white. Now, get out there and grab a piece of history. One last thing to bear in mind: a drumset featuring sequential serial numbers tends to be higher in value than sets with era-correct badges and hardware but non-sequential serial numbers.
I get emails all of the time with a basic drum description and a serial number from visitors in hopes I can unlock the history of their drum. We also have to state that much of the record keeping was archaic at best and in some cases history was destroyed in plant fires or just tossed in the garbage!. A more historical perspective and history of this practice was documented by Vintage Drum Center and can be read. From here you should be able to gather information to determine what Ludwig Drums you have and what year they were made.
Supraphonic - Click the product title or image. From the inception of date-stamping in 1960 through 1963, Ludwig solely used red ink.