These "Factory Sample" stickers were quite common in the mid /  late '70's. I have seen sheets of about 50 of these stickers for sale at collectors fairs for very little money. Sixties "Demo / Factory Sample" records always had custom labels, not stock copies with stickers. 70's and later singles, particularly plastic labelled pressings, had these stickers - white with red lettering, with pointed edging. Hope this helps!