Talked with BrewsLee and he said about patch switcher so here it is anyone can easily switch between 1.0/1.2/1.3 version.
make sure .net framework 2.0 is installed!, and Game path is C:/programe files/activision or call of duty etc... or else it will not work.
but even patch not work no problem.
Extract RAR file and you will find patch switcher with 3 folders (1.0/1.2/1.3)
incase patch switcher wont work Lets do it manually.
if u on patch 1.3 and want to downgrade to 1.0 open Folder named 1.0
You will see 3 files see pic below
just copy them and paste into Call of Duty 2 Folder and replace them , now u are on patch 1.0
do the same for changing patch version to your need(1.0/1.2/1.3)
if u dont want to copy paste again n again just make a copy whole CoD 2 folder and paste somewhere and replace file with patch files u dont hv already , by doing this u can hv both version e.g 1.0/1.3
download from link below and all credits to those who created patch switcher and provided different patch files.
https://mega.nz/#!EQhWULwQ!0vFwsGo2Mxe3 ... HEnp4rebf8
or
https://mega.nz/#!1Y10HA5L!0vFwsGo2Mxe3 ... HEnp4rebf8
pls reply if you need and other file host or any help...hope it will help cod 2 players...