It was most definitely not a stupid question and it is a lot more stupid to not ask the question and then make a mistake! So well done for asking!!
Like has been said if you need to change your IPS tags to ENOM (if .uk domain) but I think with every other TLD you are OK. Support are very good and will help you through every step of the way so I am sure you won't get into any problems. If support arn't able to do certain things (like change the tags) they will guide you through every step of the way I am sure so you won't be on your own.
Regarding the 123Reg control panel I'm not sure but with GoDaddy you can access all options related to your domain.
Hope that helps
