No, according to Davis they do NOT upgrade the sensors to the new model. I have not cracked mine open to see if I got lucky and they did for me anyway. But my guess is that they did not.
I personally do not care. With the "old" model of sensor, I was previously spot-on with the very expensive mesonet equipment installed by agencies near my house. That's all the accuracy 99.999% of guys need.
My ISS is 6' AGL, to stay with the specs NWS uses. I previously had my anemometer 33' AGL for the same reason, but for this installation I used about 13' AGL to avoid interference with utility lines in the area and to prevent vibration from the pole.
I noticed that a nice mount from vendors online start at $59 and go up from there. I have a total of less than $100 in this entire installation, and it's rock solid. I used 6x6 pressure treated post with concrete, and then galvanized fence post on top of that for the anemometer. I bought conduit bracketry to secure the fence pole to the wooden post, and secured everything with "lifetime" lag screws. If you spend a few hours in Lowe's you can come up with great solutions.