I very much doubt it would but it would likely help to some degree. I can say I did not learn till late in life and am a horrible swimmer but do a decent backstroke and side stroke which are, to me, the more useful basic swim strokes. Learning to float on ones back is most of whats needed for a backstroke. The stroke itself can be fast or slow. Most people can be in neck heigh water and just relax to allow their feet to stop supporting them and keep their face and mouth above water. If they fill their lungs with oxygen the chest should naturally go up to the surface as well. Thats like with the worst body shape.