I don't remember what became about my PG3D CDs, but I know playing in 800x600 was bad, as the scale of the screens was not fitting to make good strategies.
Can we play it in a greater resolution? then PG3D would be a very good game.

I ran across this while reading a PG 2 review . . . not really an answer for you question but may be of help as the N key may work the same on PG 3D.
"While the detail of the maps is unquestionably a strength of PG2, it comes at a cost. The units that represent your forces sometimes get lost in all that detail. It's not true 3D, but the tanks, planes, ships, and infantry are depicted from different angles so that they turn facing for movement and attack. They are quite nicely rendered, but more than once I lost an artillery piece among the buildings of a town, or a plane that was flying over another unit. That's the trade-off for the high resolution (and it's really a moot point since you can scroll through units using the "N" key), but it's somewhat of a nuisance."

The game is 800x600 only!! It does need a greater resolution mod/patch. We can barely play the first scenario of a campaign, then when the army grows it's becoming very boring.