If you really want unrooted, you can either flash the stock ROM in the 2nd post or just run Option B (unroot) in the Auto Root package. After you "unroot" it will be exactly the same as stock.
Be aware though that they plugged the root exploit used by the Auto Root package (ie option A), so, unless a new exploit is found, the only way you are going to root EL29 is to
1) use ODIN to flash a pre-rooted EL29 (or custom ROM based on EL29)
2) flash a pre-rooted EL29 (or custom ROM based on EL29) through CWM
3) already be rooted and flash EL29 through Mobile ODIN choosing to "inject" root