To summarise for the sake of clarity and I think this covers almost everything: -

You need to activate with the licence code that comes with the kit, it shouldn't matter whether you have bought an N770 or N800 kit and are using it on a N800 or N770. I have activated my N800 with the code for an N770 kit and, logically, the reverse should be true though I agree it would be nice to have someone confirm this from direct experience.

The maps are the same for both N800 and N770.

Navicore make available for download tablet specific software , i.e. N800 and N770.

The Nokia Bluetooth Wireless GPS Module LD-3W is the same in both kits.

The Nokia Car Holder part no. HH-12 is the same for both kits.

The Nokia Mobile Holder for the N770 part no. CR-81 is specific to the N770 kit.

The Nokia Mobile Holder for the N800 part no. CR-86 is specific to the N800 kit.

It seems that the N770 kit supplies the maps and software on a Mini MMC card whereas the N800 kit comes with a mini SD card.

The kit also contains a DVD with maps and software.