Before I answer this question I would like you to look at these 2 pictures and observe with detail the posture, body, engagement of parts, muscles, angle of body parts….
What you can see is that their bodies look very powerful and alike. It is good to see the look of their bodies and think that it has been developed by rowing on the water and doing specific land work that complements very well with the rowing stroke.
There are plenty of rowers that do much of their power work very specific to the rowing stroke. To give some examples they work on the water with a bungee cord to slow down the boat and make it heavier. They work on land with very light weights like bars or medicinal balls and do very dynamic and explosive work to develop their body on a way that doesn’t upset the coordination and the relaxation of the body.
The power that you want to have is the power x stroke, the power that moves a boat and not a dead weight on the gym. If you work on this direction to have power on the stroke, your rowing body will look like the body of a rower because at the end of the path we all want the same: To go fast on the water moving a boat. If we have the same goal, our bodies should develop the same way and look alike.