I had never to deal with a dev phone, but i don't see any reason why it should not work.
If the RUU is running it should do nothing bad to the phone.
If for the RUU something is wrong it will stop and will not run through.
You STAR!,
Right now seem to be back to stock, no dev options or the annoying warning not to sell it blar blar on boot. Lost all apps but who cares runs smoother
Problem now is the android version is still 4.0.4 but the sense version has changed to 4.1. Neither say restricted like before now to look into updating to the newest FW.
PS fastboot still says no device connected havent messed with it yet tho.
Time for bed and work tomo, Thanks sooooooo much for your help you now have experience of turning a dev SV into a stock.