This is obviously a CDV - larger cabinet card photos come later, around the end of the 1860's into early 1870's. Note the margin around the photo paper and the edge of the cardstock; it's much narrower than on a cabinet card. Also, the DOUBLE LINE inscribed at the edge is a way of dating CDV's to the Civil War period - later period CDV's do NOT have this feature. For this, as well as the uniform details I've mentioned above, I see NO reason this is not a fairly "typical" Union company grade officer of the Civil War. But TerryB is right: CW1234 could confirm this, and the backmark, if any, might tell us a lot more, especially WHERE it was made!