Correct and not correct.
Packard built many if not most of the engines under licence. They are cool.
Here is a little info on this development from a web site on the engines.
In early 1941, Rolls Royce licensed Packard Motors to build Merlin engines. By 1943, the Mustang P51B & C (R.A.F. Mustang III) had 1520 hp. V1650-3 Packard Merlin engines. In Canada the Packard Merlins were designated Merlin 28 and 29.
Dane