Calling it false. RPGMaker2003 shows no changed event with an envelope on Urotsuki's dream apartment desk.
Here for the room. Here is the event's first page. Here's the second and third pages.
See? No envelope.
In addition, I went through literally every Charset and Chipset (All I have to say is: 1. I have a headache 2. How the hell does Wataru manage to do so much with so little? 3. Zenmaigahara made more worlds than I thought) &... no envelope like that even exists in the files.
So, unless you can provide us with which charset/chipset said envelope is on (which should be easy, you just go into RPGMaker2003 and into the Dream Apartments (which is easy, it's map 171) and select the event on the top of Urotsuki's desk, you should be able to find the page where said envelope appears (per a switch or variable; regardless, it'll be there).
(Also, apparently you can make Orange haired Urotsuki with the drum effect!???? Or it's planned...)