先 looks like a teacher holding a pen, and 生 looks like a person sitting cross-legged with a pen, learning. maybe the symbols together mean someone who instructs someone else. Was this originally a Pictogram? just thought that was cool...
Note that 先生 does not strictly mean "teacher". 先生 is used as a title toward many types of superiours/leaders with some kind of expertise: teachers, doctors, lawyers, politicians, even the pastor at my Christian church. See this link for more information about applicability.
先 - Means "previous" or "before"
生 - Means "live" or "born"
It basically means someone who has lived through a certain skill/experience more than you.
So no, as @sbkgs4686 linked in their comment, the etymology of the characters has nothing to do with pens, and only that of 先 is even related to a person.