Just use the load Excellon option under layer.
Hell I went through the same thing. It took me 3 months to make my ECU connector only to find out that it was a single layer 6 months latter, because the part I made it from was single layer and I didn't know how copper worked. It was that gerbView and drill.txt that found it, and I only research it after I heard so many people talking about it
Holes without pads are something else again, I found that out with the TO-220 (nonconn0)
You can't do much with Gerbview except look at it where as Gerbv has ruler and stuff, but unfortunately the dimensions are wrong using a FZ gerber.