Sophia mentions all the times in which she's helped Dorothy pick out a dress, and one of them is a prom dress. However, in season six, and on a few other different occasions, it is mentioned that Dorothy never went to her prom.
The biggest goof from the episode is the war that Charlie and Buddy supposedly fought together in World War II. Rose as well as Charlie were born in 1930; so he would have been 11 when the U.S. entered into the war and unable to even enlist in the war. It is most likely the writers intended for Charlie to be a veteran of the Korean War like Blanche's husband George.