We did the tour - were very interested in DVC - and ended up buying.
You can go to SSR and tour the models on your own time. No incentives given for that.
If you want to talk to a Guide (and get the $45 or whatever the incentive is at that moment) you can book an appointment at any DVC kiosk in the parks or resorts.
From what I remember about our tour and guide, we were interviewed about why we were interested, shown a short video (similar to one you see on resort TV), walked through the models, and then had another sitdown to gauge interest/compatibility with our vacation habits. It was during that final chat we were given very specific details on ownership - points, cost, resorts, etc. At the end of the chat, we were presented with two $25 gift cards (which was a surprise to us).
It did take a couple hours from the time we were picked up at our resort by the DVC van until it dropped us back to our resort.
My opinion - I don't think I'd give up my vacation time for the incentive if I was not motivated to buy. I'm not even sure if they give it every time or if it's up to the discretion of each Guide.