Yes. Hard to say what use to use with the picture being so close and without knowing where you are putting your other trim.

Thanks for responding! Here is a bigger picture of the window. The gap is at the bottom where the black meets the wood.

now the pic is a little far back. I think I would Just raise the bottom trim to cover.

Your drywall has a little buildup near the edge and I'm guessing the trim didn't have a relief cut into the back to let it snug up to the window. I'd very carefully caulk with a thin bead of black urethane caulk.

Whatever is causing the gap can be trimmed. That piece would not be designed with a gap.

The drywall should have been smashe down/ cut prior to installing trim.

If you do decide to caulk it Anderson does have color Matched caulking.