From what I'm seeing, all it needs is a good wipedown. Hoover 541's are not supposed to be polished. That was done by vac shops to make them look like the 700 which was polished from the factory. I would NOT polish or paint this machine if I was you.
You have the original switch and bag which is a huge plus. Most switches were replaced with generic bakelite ones and the bags would often disintegrate. I'm not too sure about the cord.
In regards to age, that depends if your machine has a metal bag spreader or not. Early to mid 1920's is your range. Early 541 units had a bag setup much like the 102 and 105 where there's a fabric strip on the center of the bag that slides up and down a rail on the handle when it inflates/deflates.
Tom or Ray can shed more light into this but I hope my info helps.