1965 sparkle top Markings on keys.

[Seanfir]

Been restoring this old beauty all week. And had been looking for any signs or numbers.the pots are all 1965 within 2 weeks of each other. I used a black light and several filters on my phone to try and enhance these very faint numbers and letters on 2 of the keys... Anyone have a clue as to what these mean?You cannot view this attachment. You cannot view this attachment.

[chigalihape]

Hi Seanfir,
Hi all,

I have the same question about the meaning of these numbers on my Sparkle top. Below are the pictures of the 1st keys.
I estimate that my piano was manufactured in mid 1966 (Jensen HP from September and December 1965, preamp potentiometers from May 1966).

We find in a more faded way the stamp AR(?)1-SAN and the 94. For the other numbers I do not see an obvious link with the dates of manufacture.