Any C4 can be "dyno tuned" but all pre-1996 Corvettes use a different type of memory in the ECM such that most of today's "tuners" either lack the knowledge or the equipment or both to do it.
You need to find a "tuner" who can calibrate really old stuff and can "burn" chips.
Also, if you are wanting to do this because of a problem with the engine running too rich or too lean, if that problem is not because of recent modifications which changed the engine's air flow, and is a problem with an engine which has not been modified, I suggest that you fix the problem what is causing the rich or lean rather than trying to change the engine's fuel delivery to compensate for it.
Lastly, if the engine is stock and you are believing that a "dyno tune" will significantly increase performance, you could be disappointed. Yes, a "dyno tune" may offer an incremental performance increase but the results will likely not be "significant".