If you go back far enough ALL shifters were simply friction shifter and its was up to the rider to "Index" them properly. When Index shifting was first introduced most professional riders were incensed by the idea that they needed mechanical help to select the gears.

Old Campagnolo levers on an old bike will be friction shifters. I assume the bike only has 5 or 6 rear cogs? Indexed gears didn't even start until there were 7 rear speeds.

Anthony