Andy,
Yes, the DX database is out of date. But, when you told that APX 400 is 017712, that first part (0177) identifies the manufacturer which is used by the Kentmere films. It was just the proof that it is made by the same manufacturer.
Also, another clue was in the expiry date: almost 5 years from now. Most of Ilford/Kentmere films have 5 years of shelf life. Oh, and the lettering of that expiry date on the box is the same style.

I have some Kentmere 400 and I'm just waiting for APX 400 to arrive to try them together in 2 identical cameras and lenses.