Vintage Omega Constellation - Scratched Crystal Polishing Recommendations?

Hi guys,

I recently purchased my first vintage Omega - a Constellation 168.004.

Recently in the course of normal wear - I seem to have gotten a light / shallow scratch on the upper part of the watch crystal (pictures attached).

I'm very keen to avoid replacing the crystal if I can. Therefore I was wondering if you could help me with a couple questions.

1. Firstly - does anyone know if the crystal on this watch is glass or plastic? It appears to be a hesalite crystal on my first inspection but not sure what the best way to tell might be? Would anyone know what is typical for this watch or provide guidance on how I could judge myself?

2. Secondly - would anyone have any suggestions for the best way to polish the crystal and (at least partially) remove the scratch marks from the watch? I have read some other posts in the forum and was thinking of trying https://www.polywatch.de (hence the questions re: glass vs. acrylic). Does anyone have any potential home remedies or alternative suggestions for what I could do?

As always - thank you all for your advice and guidance.

I use Novus polishes.

I use this:
https://www.amazon.de/Acryl-Plexiglas-Polierpaste-150-Tube/dp/B001056C4W/ref=sr_1_2?__mk_de_DE=ÅMÅŽÕÑ&crid=201Q9JBYT0D1R&dchild=1&keywords=rotweiss polierpaste&qid=1634290292&sprefix=rotweiss,aps,177&sr=8-2
combined with the "Rot-Weiss" sponge its very quick and all scratches are gone.
No need to tape anything.