Just after McBride and Gahagan get in to a cab outside the bookstore, there is a close up shot of the license plate which reads "X3075". In the next shot, as the cab pulls up outside a building, the license plate reads "Z8546".
In the courtroom, Torchy's real given name is announced as "Helen" (or "Ellen"; it's hard to hear exactly), but in an earlier film in the series, when a handsome young cop was giving Torchy a ticket, she told him to replace her nickname "Torchy" with "Theresa" (or "Teresa" or "Tereza"), which must therefore be her given name. Presumably this detail wasn't considered important enough for the various screenwriters (who kept changing throughout the series) to keep track of.
During the fight in the jail, one inmate throws a stool at another inmate and misses her. The stool hits the supposedly brick wall, leaving a big dent.
At one point in the sewing room fight between Jackie and Ruby, the scissors bend - showing that they are a rubber prop for safety.