could a MacBook that's running 2 slot of equal 8gb of ram in each slot equal to 16gb, a single slot of 16gb a piece?

Depends on the model of MacBook that you have. Check that via menu bar >apple logo>about this Mac

After you have identified your MacBook Pro model, check this related article to find out, how upgrading your RAM would be possible:

MacBook Pro: How to remove or install memory - Apple Support