Help identifying Holley carbs?

A customer brought in two Holley carbs he wanted to put on his old beaters. Both are double pumpers, but I am not sure how to identify them or where the numbers are. I see a bunch of numbers here and there but don't know what I am looking for. He has a stock 305 and a stock 350, both spreadbore, so I told him these were too much carb for his vehicles and that he would need adapters and fuel line fittings. etc... Now he wants to sell them. My question is, can anyone identify these or tell me what I need to identify them? And how much are they worth - ballpark?

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