Fourteen different cats portrayed Rhubarb at different points in the film. Each cat was trained to do a different trick. Three of the most identical cats appeared in the courtroom scene where Polly Sickles has to choose which one is the real Rhubarb.
Now listen ya lug, you're in the chips now, the blue chips. So stop acting like a goon squad. This is an okay dame. She doesn't want a nickel of your dough.
Eric Yeager: stroke him very gently on his head.
Polly Sickles: Why, he doesn't even hiss.
Eric Yeager: You're now a member of the club.
At the end of the opening sequence, when Rhubarb is pursuing the fleeing dog past a shop, the film is clearly reversed - the word "Furniture" over the shop front is mirrored, as is the wording on the mailbox.
The opening cast list ends: "and introducing the newest addition to Hollywood's great galaxy of stars -- that dynamic, exciting, scintillating personality RHUBARB (by special arrangement with the S.P.C.A.) ...A.H.A. Y.M.C.A. U.C.L.A. B.P.O.E. R.F.C.)"