HW+ARR ps4 question

So I already have ARR on ps4, I preordered HW from a store but due to a mix up on their end they only had copies of the HW+ARR bundle.

Question: am I able to use the code with this and have it tie HW to my existing account or will this attempt to make a new service account and thus be useless to me?

I don't really want to accidently use the code with it and not be able to get it refunded afterwards.