Yes, unless it has changed, when you first install the software you get a registration screen which asks for your email address to register it. The trial code is then sent to your email address. You then enter this to complete the activation of the software.
You then, of course, have 30 days to play with the trial. If you decide to purchase you can then enter your purchase activation key to activate in "full" so you don't need to download it again.
Vergas pro 19 trial is asking for a trial serial number, but I haven't been given one?
I was finally able to get the trial serial, so I'm good for now. If all/most of my other Vergas Pro plugins work with VP 19, I'll be a happy filmmaker/videographer.