OK, thanks for the link. The last one I have saved to thumbdrive is setpoint620 and setpoint620_x64. The file version is 188.8.131.52. I'd say your right and 6.20 is the last full version. I already had the x64 bit version and went looking for the 32 bit and kept getting the "_smart" version. I ended up finding it on another site after a lot of searching. I'll download it again from Logitech now that I have a link.
EDIT: Where do they hid the Unifying driver on the FTP site?