Yeah, re-rendering at a higher res (or for 3D) is a tricky proposition if too much time has passed.

For the 3D conversion of Jurassic Park I don’t even know if they had the finished cg shots from '93 in their purely digital form (before they were filmed back out to celluloid), nevermind the models. I think they might have had to scan shots back in from the o-neg just like the rest of the movie. The same goes for the '97 cg shots in the SE if the Lowry master is any indication. There definitely seemed to be some filmic anomalies even on the '04 dvd. Maybe it’s even more obvious on the blu-ray but I wouldn’t know. The shot that always sticks out in my memory is when the asp swats the floating droid to the ground before luke’s landspeeder zooms into frame. Even at dvd resolution I noticed some slight wobble where there should’ve been utter stillness for those first few seconds of the shot. Unless of course the wobble was intentional on the animator’s part so that it would look like it was actually photographed…

…I’m overthinking it now, aren’t I?