I have no idea if this works. My hunch is that game patches are not tied to the system in any way.
My brother has the Smash retail cart but not a Gateway. I ripped my update folder for him so he can stay on 9.2 and still play Smash online with me. He hasn't tested it yet; maybe you can beat him to it! Here's the instructions I sent him:
1) Open your SD card on your PC
2) Inside you'll have a folder structure like this (I broke it into lines)
\Nintendo 3DS
\2d4ff57ee8a0d439599a39436be3ccd5
\19e300c83110b5203030303000284245
\title
\0004000e
\000edf00
Folders #2 and #3 (the long ones) might be different on your SD, but the other directories should be the same.
3) \000edf00 is the Smash Bros game ID where the updates are stored. Backup that folder (just in case). Delete it from your SD.
4) Download my \000edf00 folder.
http://www39.zippyshare.com/v/UHHgdw1I/file.html
5) You'll find the \000edf00 folder inside the zip. Put that folder where yours was.
6) Play Smash online with firmware 9.2????