No. Many things are different with 2.1.
I really missed the screen dim capability of Extended Preferences, so using the same idea I found a way to make it work ... it's not perfect, but works well enough.
The caveats? You must set 'Auto-Lock' before changing 'Screen dims after ...'. Also I can't get Auto-Lock==NEVER to work with Screen dim (it always locks

) Soooo..... I created an Auto-Lock value of 1440 Minutes (1 days) as a work-around --- and this works well enough for my purpose
Yea, I'm crazy ... and not a pro-iPhone developer, or anything close. But this old-time C/Unix/Fortran programmer got tired of waiting for someone else to do it .... so decided to give it a go. It's not perfect, but works. (I would be VERY happy if somebody got on board and make this work perfect

)
The only file changed: General.plist located in /private/var/stash/Applications/Preferences.app - (aka /Applications/Preferences.app). Just replace the existing file with this one and reboot (not re-spring).
NOTE: Don't forget to save a backup of your original (I like to just add (.orig) before copying the new one. Check permissions after the copy. Should match the rest of the files (664) owner root. Works on 1st gen iPhone 8G, 2.1FW.
Good luck. Don't forget to make backups, and have ssh enabled at boot-up .... just in case
Note2: Yea I know screen dim is an option with other (full-featured phone mods -- like Winterboard)
Mes