Refurbished Mac: Can you keep old software after time machine restore?
I assume the 'new' Mac isn't brand new, since new Macs don't come with MS Office pre-installed? Time Machine won't let you do such a selective restore anyway, but in that case the only way to legally keep the copy of 2016 you've acquired is to have its license transferred to you. That will likely involve contacting both the original owner and Microsoft, after which you can install 2016 whenever you like.

See also: https://superuser.com/a/1150086