Denim vest with brass buttons Size M

May be vintage? Bought it from the vintage store that I usually get my pieces from...but the tag doesn't show the usual signs of a vintage piece so I can't guarantee it. What I can guarantee is a great deal! And a very cute outfit! Great shape. Seems like a light/medium was denim with some distressing on collar. Brass buttons that say RIO on them. No imperfections that I could find.