Once you have an 'installed' LS shell....via the typical 'Installer' all you need to do id download the updated core files and copy them over [into] the existing Litestep directory.....though to do that, first you must exit Litestep as your shell....either by rebooting to Explorer...or by killing the litestep.exe pcocess in task manager...and copying them over and restarting the litestep.exe process....[I often do it the latter way]....just have your file manager open while  you do it so you can copy/move files [naturally]...
 
I'll post a link to the RC3 June 2004 for you....
http://shellfront.org/department.php?id=litestep  
a must-go-to place for LSUsers....
http://www.litestep.net/download.php?mod=93,module  
That 'should' be the link to RC3....
You don't 'uninstall'....you just extract and copy the RC3 files into the Litestep directory and overwrite the older ones.....'RC3' stands for 'Release Candidate 3'....it's a beta....but then Litestep has always been a beta at one level or another....ever since I can remember.
Whenever 'playing' with shells....ALWAYS have an 'out'....a way that is tried and true to get you 'back' to Explorer as the shell....so you don't get lost in limbo....and swearing profusely at life at large....
I did think though...back in the b23 days that we'd at least go up by full points....b24...b25...etc...each time.....not be still at b26.7......six years later....
To be honest....my themes are 'quirky' at best.
There are better themers out there ...
Main thing is to get the 'hang of it' and make your own.....that's what LiteSTEP [alternate shells] is all about....