Are these 340 exhaust manifolds

The pass side, 3418623, has a casting of 4.13.72.

The driver side, 3614368-1, has a casting of 1.7.74.

Are these dates?

Is there a pass side manifold that should have a 2.25 ID? What would be the correct ID's for a 73 Duster 340?

Thanks,
Ken