So, I dug out my '26 Buescher True Tone tenor sax . . .

[Airflyte]

. . . and was degunkehfying the neck and noticed this . . .

Are these initials?

[DaveLeBlanc]

Interesting! Sure looks like it. I can't really read cursiev that well.

[DaveLeBlanc]

Now that i think about it, if it's inside the neck its more likely a batch mark used when in production. Probably.

[Airflyte]

That could be Dave. Written on the brass before the shaping process.

If that's true, just another observation of the maker leaving a "note" on an early instrument.