Unless Boeing has recently changed to the metric system in their design work, the short answer to the question as to whether Boeing and Airbus use different systems insofar as aircraft manufacture is yes. I'm only familiar with Boeing up through the 747-400. Perhaps others can provide an answer for later models.
The Boeing Weight and Balance Control and Loading manuals I have do provide kilogram pages following the pound pages, but that the pound is the controlling unit is also stated.
Interestingly, for moment limitations, the manuals follow the inch-pound pages with inch-kilogram pages. In other words, they're mixing systems, which I believe to be unwise as the net effect is to introduce a third, hybridized system.
In the past, many 747 freighter flights that I flew were slightly over gross at takeoff due to the fact that the common conversion used for kilograms to pounds was 2.2 when the actual value is 2.20462262.
As I remember, only the U.S. and Liberia are still non-metric officially. There is a political dimension to this which you can explore at http://en.wikipedia.org/wiki/Metrication_in_the_United_States.