Just checked about 300 detailed internal pictures of the Gato class sub, USS COD SS 224 that I took during a visit to Cleveland, OH some years ago. Pentax 7 m pixel images.
Nothing that resembles the instrument under discussion. Several pictures have incline meters in them but they appear to mechanical not electrical.
My visit was to see the sub that a close friend had done 4 war patrol's on 43 ~ 45. He talked a lot about the patrols and the action during them. Shortly before I visited the sub he left us on his last patrol. Wished I could have talked to him after the visit.