Yes, it was Mars Global Surveyor's Magnetometer/Electron Reflectometer that found traces of the Martian magnetosphere. I knew that one too... lately, I've been looking at too much MOLA data and illustrations (interesting finds regarding gravity 'anomolies' from MOLA).

Interesting papers here that echo your post above (I found these after posting below):

http://mgs-mager.gsfc.nasa.gov/publications/grl_28_connerney/grl_28_connerney_paper.html

Updated info with additional findings from core and mantle models, (based on MGS's findings) etc. from the Lunar and Planetary Science conference – March 2002: http://www.lpi.usra.edu/meetings/lpsc2002/pdf/sess52.pdf (You've most probably seen those already :)

I'm not done reading those by any means... finished with the 3rd paper, which is very good, btw. It's better to print them out for reading, but my copier is out of black ink. :) Thank you, Alex.

Marcia