I think you may misunderstand recon spotting, both as an attribute of a unit, and what it is - as you have already suggested. I will try to post some pics to help.
First, there is no "recon spotting mode" to place units into. It is an action that can only be done with units that are recon capable, which I am guessing is the black text you saw in Salerno.
Here is an example of what shows for a recon capable unit, in the unit box:
Note it says recon unit, which I assume is what you saw, although it is in white text for me.
This is from 430910_01, a recon M3 Stuart unit. In this next image I moved it north to where I checked and noticed it barely had enough movement points and an LOS to use recon spotting to see a potential enemy unit.
Finally, I used the menu choice under Command-Recon Spotting, and got a hit, but just a ?:
As to the alternate Unit Box display, can you point us to where you see that? I did a search inone help guide and didn't find that phrase, so I am thinking it is something close to that.
Thanks
Rick