In a creek?
Actually,
It’s very possible that it was in a creek for a long while. So many factors in play but fresh water relics are often found in amazing condition.
Ship wrecks as an example in the Great Lakes that have been submerged for 100 years can be found in astonishing condition.
It all depends upon the exposure, if the item is constantly under water or seasonally etc.
I once found a 5 shot cylinder in the American river (fishing) where gold was discovered in 1849. That was the early 1970’s.
The cylinder was off a Baby Dragoon from the late 1840,s or a little later. It was rusty and pitted but all the nipples were intact. It had to be in that water for 100 years I would imagine.
I gave it to the local museum for their display.
Murph