Modern Vespa

See photo. The chopped off needle is from a spare carb and it's real. Is it some sort of a 50s power boost trick? I remember reading something's about su carbs being adjusted for altitude above sea level? https://www.scooterstreet.com.au/the-dellorto-phbg-tuning-bible%F0%9F%99%8F/
Some unhelpful advice here about test riding the bike after every notch adjustable.

I don't understand why the point of the needle is chopped off. Odd.

Anyway the notches are there to raise and lower the needle. Raising the needle makes it richer and lowering makes it leaner. If you run out of notches and (for instance) it's still too rich, you can go to the next leaner needle and repeat the process.

You can also get special thin washers that raise or lower half a notch.

Makes wot run richer, without actually fitting a bigger main jet, which would make the whole range richer. Bit like a cheap power jet. Ingenious really.

Will it make my bike faster or just super rich with clouds of black smoke and fouled plug?