You should be able to if they have rooms available. When we were looking into DVC we made a trip to WDW without the kids to tour SSR and the other resorts. Our guide told us just to go to the front desk and let them know that we were interested in buying into DVC and would like to see a room. We never had a problem. We even drove down to VB and looked as we had time to spare and a rental car. So I say go for it!
There are only 5 GVs at the HH resort. Because of the weekend point charts the best chance for a GV to be unoccupied is Friday and Saturday. As long as they have a villa unoccupied and clean they are usually happy to allow a tour.
I'd even call ahead to make sure they can accommodate a tour.
Except there is no DVC rep at HH. Since the resort sold out, the sales office has been closed.
The best bet would be to hope that there is a room available to see and ask someone from Guest Services (front desk would be the best place to start) if it can be viewed....