The L188 Electra had drip sticks like the Viscount and Brit.
Then we got an Electra with sight sticks. You had to look up at the lower end of the stick and it was dark when the top was covered by the fuel and light when uncovered. The only problem was if the seal around the stick leaked you got a drip of fuel in the eye.
Is this the sort of sight gauge you are looking for?