(sorry the pictures aren't working)
Using the 360-degree view on the GW webstore...
FRONT VIEW
On the model's right shoulder area (your left as you're looking at the screen), there is a purity seal. Right above that is a somewhat U-shaped, rivet-stamped armor piece. Missing one of those.
Opposite shoulder, attached to the other side's U-shaped, rivet-stamped armor piece is the tilting shield. I know two or three came with the kit; I am missing one of those.
The lil' grey knight's left arm (your right as you're looking at the screen), missing that entire arm and hand with the controller.
REAR VIEW
There are two ribbed cables near the hip area, under the two prongs that stick out and the three "dots" on the waist line. I am missing one of those cables
Sorry for such a complicated example. I bought a Grey Knights army years ago from a fella in I think Bellevue. These were in the box but they're bashed up, obviously.
Thanks and stay safe,
don