About to buy my 2nd Purchase – Code question

Hi Kriesi and Team Kriesi,

I’m about to buy my 2nd purchase and probably a 3rd, 4th and 5th one for my other 3 projects since I’m loving the theme.
But, I have this dreaded question that needed an answer ASAP please.

I bought my first enfold on Themeforest last year, August 2016.
I installed the theme on my Testing area domain/hosting and did not put the purchase code/activation yet in the theme
Now that the site is finished, (its delayed because of the client) I’m about to transfer it to their hosting and domain.
Can I use the purchase code/activation on the theme even if its 8 months late of not using it?
and If I did use it on the testing site, can I move that to another domain and uninstall the one on my test area?