How do you define "little" is the main thing.. The definition of a relative/subjective term is something that might mean different things to different people.... or "modified or affected by personal views, experience, or background"
Example... My 1964 Chevelle convertible had rusted through floor pans and trunk.... In California, it would be described as a "Rust bucket" that same car, on the East coast could be described as having "little rust" and it would sell immediately(which it did) since on the east coast, they salt the roads in winter, and most cars from that era are completely shot. So RELATIVE to any other 1964 Chevrolet in the area, it has "little" rust.. If I tried to sell it in CA stating it had "little rust" I would be laughed at...(which I was,,,
"little" is absolutely a relative/subjective term.... I am sure that my 'Little" is going to be different than yours.... Go ask several people to bring you a "little" of something, and see how many different amounts you get.....
As far as function, If it does not work properly because of rusted parts, then you might have something....
Also,, It was stated that it had to be hammered apart... How much of the rust was visible before disassembly??? The large spot of rust looks to me like transfer from the inside of the other tube it slipped into... Have you tried wiping it off???
Always be careful of terms that are not exact like "little" "some" "many" etc...