What makes you think blend door actuator location is different between 91 and 94?
Actuator seems to be same part for 91 and 94.
YouTube you saw probably is this
https://m.youtube.com/watch?v=l9wTpK6nBZA
and applicable to 91 as well.
In any case, removing the dash is not that difficult. Just time consuming.
Edit - I saw a post on Corvetteforum where later cars the actuator was moved to the bottom for ease of service. I still cannot picture how that would be possible...