No it will certainly not. 4.2 contains no updates for the console which you don't already have and was only designed to remove homebrew. There's a reason we plaster Don't Update to 4.2/4.3 all over the guides.
A reinstall of the 4.1 system menu will accomplish what you're attempting in a 4.2 update. Not sure if it'll work but you can try. Follow the offline section of this guide for instructions on grabbing the files you need from NUS.
You'll want IOS60-64-6174.wad and the 4.1 System Menu 449.wad.