Originally Posted by BUFF
Most likely mis-marked by the seller.
I agree. I have never heard of a 25-3 being offered in .45 ACP.
You can look into the chamber of either round from the rear, and easily see the difference. The .45 Colt cylinder will be deeply chambered, with a taper leading into a shorter throat, while an ACP chambered cylinder will have a shorter looking chamber and a sharp step at the end of the chamber where the case mouth butts up, since an ACP case headspaces off the case mouth.