Black onyx/rubber only at 3,6,9,12 hour markers

Hi all, I just bought a 166.011 Seamaster that only get black onyx/rubber inserted at 3,6,9,12 hour markers. The others markers don’t seems to have that or any trace of black paint on them. So do you think that it was normal or uncommon!?

The real question is why you think they might be made of rubber?

Well If I remember correctly, I saw a clip on Timeless History youtube channel and he said they are made of onyx, rubber or painted

This topic has been discussed in the past when it was raised by new members who, IIRC, had seen the same, or similar internet clip.
The concept of rubber inserts appears to have originated from one source, with no evidence to support the premise - and was definitely news to the OF collective.
As far as I know, Omega used onyx or jet as inserts in their vintage watch indices, until they decided paint was a cheaper option in the late 60s.
You should never say never with Omega but if there is any evidence that rubber was used at any point (not some chap on youtube saying so) I would very much like to see it presented here.