I think I'd just say that it was won as a drawing, etc. (any details you might have/remember including place) in 2007, Maker Unknown
I will be making a label for a top I'm finishing that I found a thrift store, basically saying:
Grandmother's Flower Garden
Maker Unknown
Handstitched, fabrics circa 1970-1980
Machine Quilted by Me, 2019
I'm going to include a scan of the Goodwill tag on the label showing the $5.99 I paid for it because I'm goofy like that.