Yes, MS supports any retail copy with the best funded Tech Support in the business.
I also bought Amazon (for the free shipping) pre-order Upgrade and have gotten MS support already.
They are required by policy to troubleshoot to completion any issue, even elevating to a research team that communicates with the developer teams, as long as customer is cooperative.
As with any tech support you may get a bad agent or someone having a bad day. I always politely hang up and call back.
In the past by being appreciative and eager to learn, I have gotten a full education in clean reinstalls w/o bloatware, virus hunting, optimization, etc. - worth far more than the price of the product.