the answer is yes - all grains have traces of natural yeast on them - milled/processed ,,, the yeast remains.
if you buy/use/maintain a sough dough starter, it will gradually morph to include yeast types in the flour you bought/use. the woe of many a bread baker hoping for 'the old fashion San Fran sour dough'
the level of naturally included yeast is so minor that bakers add yeast to ensure timely and 'proper' results.