Default Q: Are steps different to unroot w/s-on if already stock, rooted and s-off?

So I have my HTC One M7 rooted and s-off but need to return it because of the purple camera issue. I found this guide but I'm not sure if the RUU step is necessary since I'm already on stock and have removed the tampered flag:

http://forum.xda-developers.com/show....php?t=2358738

Can I just remove root and return to s-on or do I have to go through the whole process with RUU?

Here is my bootloader info if that helps:

*** UNLOCKED ***
M7_UL Put SHIP S-OFF RH
CID-T-MOB010
RADIO-4A.24.3263.09
OpenDSP-v32.120.274.0909
OS-4.19.531.10
eMMC-boot 2048MB
Feb 3 2014, 18:42:45.0