There seems to be a lot of confusion about this in the WP community. To clarify, the 8170 update is a Windows Phone wide update from Microsoft. It is an OS update. In the "about" section of your phone it will change the OS Version Number.
The update for the Lumia is a firmware update for the phone and will update the Firmware Revision Number in the about section.
And for those who might want to know, the Lumia firmware update will:
"include no. of charging related (high voltage charging), power optimizations and some performance related updates that will further push your Lumia 800 usage. Also the default camera mode in Lumia 800 will be changed from Macro to Normal mode. Earlier there were reports about slow auto-focus and poor low light performance issues in Lumia 800."