All I know is that Smallbear says that they get their PT2399 from the actual Princeton factory so there should be some benchmark to compare to if unsure.
With regards to smd chips make sure you note that there's two differnt footprint sizes AFAIK out there (150 mil wide or 300mil wide), I'm just getting parts in to do a PT2399 smd delay with chips that I got from Smallbear (with the 300 mil footprint).