Not just 737's either in the USA. I've seen it done on DC9's and 727s extensively (and exclusively - no tugs used anywhere in sight in those days) at St Louis, Mo.
Also witnessed it at Atlanta, LaGuardia and ORD although not exclusive means of pushback. I'm talking 1976-78 timeframe, don't remember seeing it done in the 80's, but you know what they say.