Either they did or soft tissue survives magnitudes of years longer.
But here is some other research:
I
sciencevsevolution.org/Holzschuh.htm
RECENT C-14 DATING OF FOSSILS INCLUDING DINOSAUR BONE COLLAGEN. Are the results a confirmation of rapid formation of the geologic column as modern sedimentology studies have predicted?
AUTHORS: Josef Holzschuh, Jean de Pontcharra, Hugh Miller
ABSTRACT: The discovery of collagen in a Tyrannosaurus-rex dinosaur femur bone was recently reported in the journal Science. Its geologic location was the Hell Creek Formation in the State of Montana, United States of America. When it was learned in 2005that Triceratops and Hadrosaur femur bones in excellent condition were discovered by the Glendive (MT) Dinosaur & Fossil Museum, Hugh Miller asked and received permission to saw them in half and collect samples for C-14 testing of any bone collagen that might be extracted. Indeed both bones contained collagen and conventional dates of 30,890 ± 380 radiocarbon years (RC) for the Triceratops and 23,170 ±170 RC years for the Hadrosaur were obtained using the Accelerated Mass Spectrometer (AMS). Total organic carbon and/or dinosaur bone bio-apatite was then extracted and pretreated to remove potential contaminants and concordant radiocarbon dates were obtained, all of which were similar to radiocarbon dates for megafauna.