Amber is one of the better preservatives of DNA, so dinosaur extracting DNA in amber might be possible, but there has been no success so far in extracting DNA from any animal. Some studies looking into DNA from flies in copal, a pre-amber material, failed. While amber preserves DNA longer than other "fossilization" processes, the DNA still breaks down. If there were partial sequences remaining, putting together a longer string much less a complete genome is probably impossible. Pushing the age of the specimen back to Cretaceous time is just adding more time for degradation. Attempts to extract DNA for the La Brea tar pits has been largely unsuccessful as of a couple years ago, although there was one report from the 1990's where saber-toothed tiger DNA was isolated. The problem at La Brea is with asphaltification of material. I wonder if something like that could happen between the organic compounds in amber and tissue from the specimen.
That being said, on the optimistic side, there might be enough fragmented nucleotide sequences that might allow some sort of synthesis and filling in gaps.
We never had any reason to study Cretaceous or Paleogene ambers in any exploration work, so I don't have any data base to work with.
