When Joe first rides Black Beauty, the horse kneels down for Joe to get on him - Black Beauty only has a headcollar on. When you see Joe dismount, the horse has both saddle and bridle on.
Ginger's blaze on her head changes through out the movie. That
means there was more then one horse playing her and/or the blaze was painted.
means there was more then one horse playing her and/or the blaze was painted.
When young Joe is saying goodbye to Black Beauty at the new stables and removing his tack, the bridle switches between being on and off as the camera angle changes.
When John and Black Beauty arrive home after the storm, they are perfectly dry, despite the fact that John falls into a river and Beauty had no shelter from the rain.
When Black Beauty is walking around and around in his stall after Ginger goes crazy, his bearing rein is loose and practically undone. However after Reuben examines the wound on Black Beauty's leg, he undoes the rein.
When Black Beauty is put in front of the carriage for the first time, you see Ginger raising her lip and whinnying. This lip raising is actually a (trained) Flehmen response, and horses don't do that while whinnying but while trying to better smell something.
In some parts of the film the horse playing Ginger is clearly a gelding. Ginger is supposed to be a mare.
The foal playing Black Beauty is a filly but Beauty is supposed to be a colt.
Black Beauty's mother, at the beginning, is freeze marked - a means of identification not available in those times.
After Ginger causes the accident outside the stately home, Black Beauty is taken into the stables, the soundtrack makes it sound as though he is wearing shoes, but as the camera runs along the ground it's clear that he isn't shod. Most working horses would have been shod at this time.
When Black Beauty is dreaming of Ginger after seeing her in the city, a crew member can be easily seen releasing Black Beauty and then ducking into the cover of the grass. Also as the horse runs off, the lead line attached to his halter flaps up into the air.
When Merrylegs is opening all the stables and Black Beauty says "open mine too!", in the upper left corner you can see the arm of the trainer telling the horse playing Beauty to release the pin.