I have defined the product "MacBook" (product.template) with product variants (product.product), the variant being the serial number (since MacBook assigns serial numbers to all products like most companies and products).

There are several models of MacBook (for instance we carry different year MacBook Airs, MacBook Pro's, MacBooks)

Each of those would actually be a separate product though. A MacBook would be a product (product.template) and a MacBook Air would be a separate product and then each would have the serial product variant (product.product).

Lets say we have 10 MacBook Pro's, each one has the variant for it's own serial number (for instance, the MacBook I am on now is 451161MPF5X. When the customer picks out a MacBook Pro and I am on the verge of selling it, How will I identify that MacBook the customer is purchasing corresponds with the serial number they are getting? I don't want to select MacBook Pro as the product and then the serial number be the wrong serial number that goes out the door.

Or are you saying when  I go to select the product being purchased that I will select the MacBook Pro with the serial number of
451161MPF5X? I hope this question makes sense. This is new to me but so far have seen that Odoo can be very powerful. Now it is just a matter of learning to use that power to create modules that we can benefit from.