One question about GYPSY...

I agree with the general consensus that Gypsy is one of the best written and constructed American musicals, but one thing has always bothered me. When Mr. Goldstone shows up to book the act on the Orpheum circuit, he is referred to as "Mr. Goldstone" throughout the scene (and song). Suddenly at the end, everyone calls him "Mervyn Goldstone." How did they find out his first name?