I don't usually find date codes on the pumps either, although I'm pretty sure I have seen some with date codes, not necessarily C8- pumps, but most of them I have had weren't dated. So, a Non Dated pump would be fine for me as long as it is the Factory Correct Pump.
I would like to make sure I source the Factory Correct Pump for this motor, it might eventually be Concours Judged. Its the only thing besides a Carb that is not correct. The Motor had an 85-86 5.0 Holley Carb on it. I got rid of that and would like to also find a correct carb but thats a Needle in a Haystack kinda thing.
I also posted a wanted ad for a pump, so if you have one available then please PM me.