The red film is not original.
It has most likely been put on to cover marks from fingerwear to the buttons.

Martin

I thank you for your reply! Sorry to ask again: the seller swears that they did this at the factory. The rest of the deck is just in perfect cosmetic condition.

They didn't!
One thing is, that using a color (particularly one like this) completely destroys the aestetics and the design language,
accentuating the buttons like this would be just as wrong as fitting blue LED lights in them.
another thing is, that they would never allow airbubbles under the film.

Martin

The whole button area looks as if it has been painted grey.
It should be stainless steel with a fine "grain".
It was probably scratched or badly worn (which is quite normal), and somebody tried to make it look "nicer" or fancier...

Martin

Martin, I thank you! On your advice, I have almost abandoned this purchase. But it would be good if there were still opinions of connoisseurs.

If the rest is pristine, it would merely be a matter of refurbishing or replacing the button panel if you want it back to original.

Martin

Which of the experienced can say: was a protective film provided on these decks at all? Or were all of these 4000-6000 decks sold with a bare keyboard?

Can someone remember that old time as it looked in the store?

From factory the keypad has a coating to protect the stainless steel from finger-acid.
This is what wears through with heavy use.
It's a clear coating (no color).
It covers the whole panel area (not only the buttons), it cannot be pulled off and it's nothing like a film.
It's like this on all Beogram 4002/4004/6000 and also on Beomaster 6000 4-Channel, Beocord 5000 etc..
Beogram 4000 is different, because the buttons are eloxated aluminium, not stainless steel.

And yes, it was like this in the stores.

Martin