My friend has a very nice 68 Charger and the windows are very difficult to roll up and down, the panels were removed and inside was inspected, nothing looked bad. A small amount of lube was put on various pivots and slides but its no better. Another friend is having the same problem, anyone run into this before?

Try shooting some WD40 into the "clutch" unit that the winder handle goes on. There will be a very small gap where you can force some lube into
the clutch.....worked on my 66 Satellite.
Did you try lubing the slides at the front of the glass that run in the vent wing channel??

Do not lube the slides in the front channel! The leading edge of the glass has a thin plastic cover with a felt like finish attached to the glass. You can replace them but they are not supposed to be lubed. What kind of weather strips/ cat whiskers do you have between the top of the door and the side of the door glass. If they are the rubber ones, they really make it hard to roll the windows up and down. If you have the rubber ones, you want to replace them with the ones that are more like the original "cat whiskers" configuration.

OK....not actual "lube" then. Use a silicone spray. We used a lot of that spray atthe dealership back in the late 60's for this very reason. Stopped a lot of problems in the icy weather too.

Yeh...I'm that old.

One car has new correct cat whiskers, replaced because he thought that was the problem. My 66 Coronet is now doing it too, has very low miles, all stock.

Those mylar whisker sets are about $100 IIRC. Not something you want to mess up.
I just installed the door and quarter glass in my 68 and that coiled spring inside the area where the handle attaches was all gunked up with old, hard grease. I scrubbed it in the parts washer and then put some new lube on it. That and lubed the tracks where the nylon guides slide.
Goes up and down nice and smoothly now.

cool car in the photo, I'll follow your advice on mine then do it on the other cars if it helps mine. Your help is appreciated.

aside from lubing all the areas mentioned above, make sure the the channel (vent window) is straight. there are pivots at the bottom of the inside doors which can move and ever so slightly cause the window to bind. look down there with a flashlight and you'll see what i'm talking about.