Seat Belt Question

[lkt1954]

Back a couple of years ago I bought a set of seat belts from Ecklers (they are safetyboy brand). They are the retractable lap and shoulder belts. I'm also adding a 3rd person middle belt.

In the picture is the buckle end that was in the package. I don't see how this is going to work. I would appear to me this buckle end is for bucket seats, not a bench seat (which I have).

Am I correct on the application of the buckle ?
Can I just order an adjustable buckle end for like Summit and it work or do I need to get one from Safetyboy?

Thanks