Is this a brown marinated stinkbug?

It sure looks like the Brown Marmorated Stink Bug. (BMSB). Note the striped legs, antennae, and smooth "shoulders." Here's more information: https://extension.oregonstate.edu/brown-marmorated-stink-bug
The trick is to be able to identify them early. Take a look at this OSU publication, which shows what the BMSB looks like from eggs, through juvenile (nymph) stages, to adult: https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9054_0.pdf

If you recognize the eggs and the nymphs and destroy them it will help to keep the population down. According to OSU: "Currently, monitoring and correct identification are valuable tools in assessing infestations. Excluding the pest from agricultural hosts provides the best pest management tool, so far. Biological control looks promising in the future, but more research is needed to evaluate its impact on BMSB populations."

I consulted with our bug ID expert and he confirmed - Yes! This is a BMSB.

"Yes, that is an adult brown marmorated stink bug. One of the easiest ID characteristics to see in a photo is the white banding at the joints of antennae near their tips. Here is a link that shows characteristics of BMSBs that distinguish them from other superficially similar-looking stink bugs....

This pest will overwinter in homes. During the fall, BMSB aggregate on sides of houses and buildings. They then work their way into the buildings through cracks and other openings. They can be in a semi-dormant state during most of the winter, but warm spells cause them to move around and become more noticeable. The best way to prevent them from entering homes is to seal all the openings with caulking or other material to exclude them. Once in the house, vacuuming them is the best way to capture and remove BMSB. Crushing them can cause them to release their defensive aroma, which is disagreeable and lingers for a time."