need a matching 1920 carb for my manifold

Your older carb looks like a Tomco rebuild so it might not have any numbers stamped into anymore. They sometimes bead blast those things to an inch of their lives! Both places you have circled are where the stampings should be. If there is nothing there, we'll just have to take our best guess as to application. I'll go look through mine and see if I have a matching pair.