Niblet, to answer your question. It looks like from your pictures you have the correct looking pump. Appears yours has the bent tube coming out the back that was used on the 350 engines. The date stamp on the aluminum housing is the only way to have an idea if your pump came with your car.
As the bent tube pump is rare in comparison to the straight tube pump (used say on the 327), it is unlikely that someone changed out your pump.
However the rear plates on these pumps can be interchanged.
Meaning if you find a straight tube pump with the correct date and you NEED a rear plate with the bent tube, you can disassemble the pump and convert it to a bent tube pump.
Can't Repeat, to answer your question. The info on the site about date codes might list a separate code for Corvette. My understanding is Corvettes even if the date was the same had a different alphabetical letter code on the pump.