They're not green sunfish. I do this for a living and sunfish are my specialty. Hybrid bluegill have smaller mouths and rounder, more compressiform (like a bluegill's) bodies than a pure green sunfish. Here is a picture of a hybrid bluegill that was right at 12" and weighed right at two pounds, caught by me from a pond I was managing:

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Here is another hybrid, this one with a larger mouth but still significantly smaller than a pure green sunfish's, from the same pond, 1-3/4 pounds:

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Here is a photo of a pure green sunfish - note the larger mouth and more elongated body:

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Here's another:

8'' Green Sunfish (5-10-15) - Bluegill - Big Bluegill

And another:

Nice Green Sunfish - Bluegill - Big Bluegill

Here's a sunfish identification guide which notes the larger mouth as a defining trait of a green sunfish:

TWRA - Tennessee Wildlife Resources Agency - Sunfish Identification