I do not think the white looks too new based on the photos alone.
I know that when you photograph white paint on a helmet it actually looks much brighter then it does in person.
Also the touch up appears to be dark green to me.
It looks like the painter was trying to even up the bars.
I would not rule it out as a post WWII paint job simply on these photos.
To say that someone ruined a good helmet is jumping to conclusions based on the photos alone IMHO.
Also another possibility is that the Capt bars were painted for Korea or later.
Just my two cents.