That's an upper limit, and know one has any idea of how something that should be completly broken down in 200k years looks like its still basically intact.
Golly gee whiz, no kidding.......... To admit what the the bones actually are screaming to them would mean they would have to flush their world view, not to mention their PhDs down the toilett.
The amino-acids in the fossils means they are most likely far far far less than 200k years old. It also means that the other dating techniques that date the age of the surrounding material are in question.
Whether anyone thinks they look like chicken bones or not has nothing to do with the discussion.
Dinosaur bones have been found on a lot of places on this planet - and there are a LOT of species of dinosaurs that have been found (stegosaurus, tyrannosauras, raptors, triceratops, etc see http://en.wikipedia.org/wiki/Dinosaur). And of course, the bones of what evolutionists call modern mammals are relatively common in recent sediment (e.g., humans, monkeys, elephants, whales, dolphins, cows, hippos rhinos, llamas, horses, dogs, wolves, zebras, sheep, cats, tigers, even mastadons, sabre tooth tigers etc).
Has anyone ever found a dinosaur in the same layer as a modern mammal? Has anyone ever found a dinosaur in a layer above a mammal?
Has anyone ever found evidence that a dinosaur ate a modern mammal? (I know that the bones of their prey have often been found in the stomachs of dinosaur fossils).
Wouldn't one expect that somewhere on the planet the Flood would have mixed these bones into the same geologic layer or put mammals in lower layers if they lived at roughly the same time?
As far as I know, no modern mammal has been found below the KT boundary and no dinosaur has been found above it. But if there is evidence to the contrary I would love to see it.
There are certainly a lot of bones out there to test the hypothesis (that any modern mammal coexisted with any dinosaur) and over 150 years of people looking.
p.s. There is a nice little book called the Dragon Seekers that looks back at the dinosaur hunters in the hundred years of so before Darwin and some of the theories they suggested to account for the lack of overlap in the fossils.