[CR] bertin versus andre bertin (and mixed tubes)?

I am quite familiar with Bertin bikes, and their graphics. But I came across a bike branded "Andre Bertin" with very different graphics.

http://picasaweb.google.ca/pjstock/AndreBertin

I presume these were from the some maker but at different eras when their look was different. Can anyone confirm?

I was then directed the the CR site where another query popped into my head.

This Bertin has a 531 frame and Vitus 788 forks.

http://www.classicrendezvous.com/France/bicycles/Bertin/bertin_moos.htm

I've never seen a bike with mixed tube manufacturers before. How unusual is this? a maker combining Vitus and Reynolds, or other makers?