The ERTL New Couplings: 2003-2004

Also not every engine had a U-hook from 2003, I remember when I got my ERTL 2003 Duck it came with two hooks NO u-hook. Maybe it was an old model in a new packaging by mistake?

The new style packaging came out in 2002, engines would still have the older style couplings. In 2003, the coupling system changed. Hope this helps.