Mono Newbie

I have some wire recordings from the 40’s & 50’s burned to WAVE files on CD. I set the Audacity Preference to MONO and Drag the file to the Audacity Icon. It dutifully opens it. But, there are two tracks instead of one. They are exactly the same. Is there a second place I have to inform it that the file is to be MONO?
Mac OSX 10.4.1

CD tracks are always 16 bit 44.1 kHz stereo.
If it is a CD track of a mono recording, then both the left and right tracks will be identical.

If you want to convert it back to mono;

Click on the little down-pointing triangle next to the track name and you will get a drop down menu.
Select “Split Stereo Track” from this menu.
On one of the tracks, use the same menu and select “Mono”.
On the other track, click on the [X] next to the track name to delete the track.