301 an old URL with a ? in the URL?

[DanDeceuster]

I am redoing a site and the URL's are changing structure. The client's site was in magento and in the store they would get two URLs, for example:

/store/categoryname/productname

and

/store/categoryname/productname?SID=dslkajsfdoiu947598whouieht983hg98

Do I have to 301 redirect both of these URL's to their new counterpart? Both go to the same content but magento seemed to add these SIDs into the navigation and Google has both versions in the index.

[watchcases]

A 301 redirect is sent to the browser as part of the header of the page. If Magento returns the same page for both URLs, it should return the same header information and you should only have to make the change once.