If that much time has elapsed, I would let the "sleeping dog lay"
I would think that too much time has gone by to issue an addendum to your report and if you do mention it at a later date you will be creating a whole bunch of problems for your self.
What would you say to the person? Kinda awkward situation if you ask me.
My agreement has a statement that allows me to modify my report for up to 5 business days. This way and I have already did this once before, I can issue and addendum without too much worries.