“The idea that the soft tissue traces were locked inside the rest of the fossil,”
Wasn’t a fossil.
“During microscopic examination of the fossilized remains, it was noted that some portions of the long bones had not mineralized, but were in fact original bone.” [’had not mineralized’ means ‘hadn’t fossilized’]
http://www.detectingdesign.com/fossilrecord.html
As for calling the age of the T-rex into question, you don’t need to worry about that. For you, nothing will ever call it into question.
It was a fossil. It says so in the quote. “During microscopic examination of the fossilized remains”.
Almost the entirety of the bone had been mineralized, or to be accurate, permineralized. It was only once they broke it open did they find traces of bone matrix and proteins locked inside.
So it was a fossil.
Also, that quote isn’t even referring to the T-Rex that got the acid bath. It’s from the the one in 1990 that was thinly sliced. The one that the veterinary pathologist picked up on.
The T.Rex that got the acid bath, Bob, yielded up something of particular interest. The presence of a medullary bone, which is something found on modern birds. It’s a calcium-rich structure they create on certain bones before they breed. Once they start producing eggs, they draw on the calcium in the medullary bones to create the shells. After comparing these samples to that of modern ostrich and emu, they have nearly identical structures! That’s pretty cool.
Which is why these discoveries are so exciting. It’s possible that many of the predictions made by the theory of evolution that were previously untestable, can now be tested like in the example above.