I did it on my 90 740T.
You may need a narrower grille; the US spec 760 will work. It's chrome, though.
As I read the kit, it comes with the lower trim piece. You're getting a heckuva price...my Hellas from Hamburg, GE cost right around $600 USD.

You may need the US spec 760 grill brackets too. There are four bolts that hold the headlight assembly to the brackets and the fender...you have to interchange the long ones that are used on the us spec grill brackets and use them on the headlight assemblies at the fender. The short fender bolts are used on the grille brackets (the headlight assemblies bolt to the grille brackets).

The kit picture shows the grille lines up with the hood bulge...that only works with a 760 hood. My 90 740 hood is wider than the 760 grille. It doesn't look all that bad unless you are picky or know what to look for.

And you'll need the 760 grille to radiator support fairing to clean things up.

At least this is what I had to do on my 90. Maybe the 91 740 and 760 had the same width grille.