How to change the Messaging and keyboard apps to stock ones on LG Optimus Net P690 running Cyanogenmod7?
Download the apk files of the stock keyboard and messaging apps and copy them to the current directory. You can also copy them from /system/app/ directory in the system.img file(use magiciso to mount it) present in the stock firmware file(usually .tar) Start an adb session and execute the following lines:

Mounting system partition as read-write:

$ adb shell mount -o rw,remount -t yaffs2 /dev/block/mtdblock03 /system


Removing CM's apps(change the names):

$ adb shell rm /system/app/CM_messaging_app.apk
$ adb shell rm /system/app/CM_keyboard_app.apk


Installing stock apps(change the names): 

$ adb install stock_messaging_app.apk
$ adb install stock_keyboard_app.apk


I would recommend 'hacker's keyboard'( https://play.google.com/store/apps/details?id=org.pocketworkstation.pckeyboard&amp;hl=en) over the stock keyboard apps though.