I have ALWAYS labeled my quilts, it does not matter if i'm keeping it, if it's a gift or if i am selling it. the ones i sell i include on the label, the name of the quilt, my name, town, state, country. the date (at least the year) and the fiber content/laundry instructions...
just like if they were going to buy a quilt from JC PENNEYS, or POTTERY BARN...every thing you sell should have some sort of label on it, even if it's just treatment instructions , where it was made, and a date.