how do I know I got the MacBook Pro 2020

In your instruction booklet it will tell you what product it is OR since you have the sale receipt then you can call ahead that the sales person gave you the wrong product and return it to get the right product.

If you are referring to the 16" model, as indicated in your signature, there is only one version of 16". It was released in November, 2019, and has not been updated or replaced.