Negative scans

I have just ventured into having some b&w negs scanned as tiffs. When I open the file in PS CS2, I am presented with the option of:

Leave as is (don't color manage) or to assign a profile such as Adobe RGB 1998, etc.

When I leave it as is, and open the Channels, I find that the 3 color channels are present, so I assume that the scan was a color scan. (I didn't think to ask.)

So my question is, what is the difference in how I open this b&w scan?

Thanks
Paul

I would open as is. Adobe RGB is more for printing only and always looks washed out to me. Not good for showing on a monitor.