Vintage WWII/ Vietnam Era Guidon Unit Flag US Army Military With Pole Free Ship

Came from a local estate, I dont know anything about it. Flag itself is 16" long and 13" tall. Is mounted to a pole that is 49 1/2 long including the spear tip. The number 1 and the init insignia are both sewn on. Flag is in nice shape with some minor wear. Pole is in good shape, has some light wear. Flag is affixed to the pole with staples.

It looks pretty old to me, I believe it dates from either WWII era or Vietnam era.