I think you will find that if you purchase a Sachsen-Ticket from a Bahn automat, it will come out with the day of validity already printed on it. During the process of buying it, the machine will ask you for the date you want to use it.
I am looking at two Tageskarten that I bought from a VVO automat in a small S-Bahn station (Krippen) outside of Bad Schandau in the VVO in 2012. I believe one was an entire network ticket as I used it to go into Dresden and back; the other was for local travel. They did not have the date printed on them. They have three triangles on the right hand side pointing to the edge where I cancelled (date stamped) them.
I also have a single trip VVO ticket that I bought at the Bahn station in Bad Schandau when I arrived and used on the bus to go across the river (bridge) to my accommodations. It almost looks like the tickets I bought at the Krippen S-Bahn station, but it's a little wider. I think I bought it on the bus from the driver (or possibly from the Bahn automat in the station). It has the validity date printed on it and did not have to be cancelled.
So, the bottom line is, whether or not the ticket has the date printed on it or is an undated ticket and has to be stamped depends on where you buy it, but if it comes with the date printed on it, you will be asked what date you want when you buy it.