
I suggest that you find several like Month coded cars like your Camaro 05C (if this is possible at this date in time) and collect data to show what they have (the more the better)... I further suggest you keep what you have unless you know with out a doubt it was changed somewhere by the previous owners... if it was a dealer replacement you should still use it...as that is part of the cars originality... once parts are replaced, the car can never be 100% original... that's why a 100%-er is so rare...
yet these days everyone seems to have one... back in the day 40 years ago and well into the 80's these cars were sought mostly for one thing, Hot rod GO Fast mobiles... everyone was swapping out manifolds for headers and carbs for Holleys, shifters for hurst shifters (because they worked!), etc.. more of the these cars were altered than what we seemed to have today...so with this knowledge and that the factory was about production and the "Gett-er done" was to use any part that was available to keep things moving (i.e. within reason) you could have an original shifter.
If it was switched out then you can use the collected data to consider which one to go with... Good Luck and I'll keep a look out for info for you too.

just my 2 cents.. you probably already knew all this...
