No Mode C why is this sticker on the transponder and why?

[Miksnave]

I am interested in proper ATC when I will need to be squarking my ALT
Is this already happening? The sticker indicates otherwise.

[jmarkows]

If I remember an old post from someone at JF correctly, the plane they used to model the Warrior has that sticker, and the transponder Mode C doesn't work.

In the sim, it works, even though it's tagged as broken.

[GunStrauss]

Weird, not possible to clone-stamp a little in Photoshop? If it does work, there should be no sticker there?