If it were me, I'd definitely put the seller on the Hot Seat and ask her why the description doesn't match the serial number in the photos. The bag in the seller's photos IS a style 378 which
Coach lists as a Hamptons Weekend Patchwork Tote - I can't find Coach's measurements but I'll accept the sellers. Style 1481 is a Hamptons Weekend Patchwork SMALL Tote, measurements 8x8 inches. BIG difference!
Pictures of both are below, the 378 on top and the 1481 on the bottom. The pictures aren't to scale but you can see how much bigger the 378 is just by looking at the proportions of the bags compared to the leather hangtags and the Coach Leatherware patches above the front pockets.
BTW, the bag in the listing is genuine.