Guidance on vintage blue Tudor 9411/0 Snowflake

[Tobiasr]

Hello vintage Tudor/Rolex cognoscendi,
I am looking to your guidance on the authenticity of a vintage Tudor snowflake 9411/0 that I am considering buying. I think it is very nice, but I am not sure on
a) the model number between the lugs - looks a bit "handwritten", but I recognize this problem is with many vintage Tudors.
b) the movement. Have not seen such a rotor on such a Tudor.
Perhaps you have other observations too.

Thank you in advance!
Tobias