Install a new unused QBD for Mac 2016 version.

Warm greetings, @Nobbyo. I understand you want to install unused QuickBooks Desktop Mac 2016 and get the validation code. 

Yes, if your computer is compatible with QuickBooks Desktop Mac 2016, you can install it. 

Meanwhile, you can contact our QuickBooks Desktop Mac support to request validation codes for older and unsupported versions. Our designed team possesses all the necessary tools and information regarding your concern, which is beyond the scope of what can be done here in the Community space.

Moreover, I'll add a comprehensive article that will guide you through using QuickBooks Desktop to ensure a smooth experience: Get started with QuickBooks Desktop. 

I'm still around to assist you further if you need more information about the QuickBooks Desktop Mac 2016. You can utilize the reply button below to enter your queries and concerns. I've always got you covered.

@Nobbyo 

Which MacOS do you run?

I have an older laptop that is still High Sierra that I was planning on using.

@Nobbyo 

If the license is a pre-registered license and the version has outdated, there is no guarantee that Intuit will provide the activation code. You should ask the seller for a guarantee that you can return the license.

We can offer another option to run QB Desktop 2016 or 2019 on your old machine with a non subscription license. Contact me in private for details.