Yeah but it depends if you wanna play online or not.
You can keep openbeta, ECX and ESF 1.2.3 and play online this way.
1. Install ESF 1.2.3
2. Install ECX over it.
3. Rename that folder to ECX
4. You can always keep the openbeta since the folder is named esf_openbeta by default.
5. Then reinstall ESF 1.2.3 in the HL folders.
6. If steam was open when u did all this close and restart.
And for EVM, you have to change the name of the Game itself in liblist.gam When u do that then you cant join servers coz itll identify ur game as whatever u named it.
Rename your old esf folder to soemthing.
Reinstall eSF. Install EVM. Then rename the ESF folder containing EVM to EVM. Then go into that folder and open liblist.gam file with notepad. Rename the game name to EVM.
Rename the old ESf folder to ESF.
Restart Steam.
Voila!