You can, in fact, safely shoot an antique pistol that is in good condition
Several of you have asked the question if I have fired the hypothetical pistol with which I began this thread. I have not. I am still looking for the right antique pistol, and acquiring the funds to purchase the "right" pistol. But finding such a pistol is NOT the topic of this thread. Please leave comments on that for other threads in the black powder forum.
This thread was started in order to cover a topic on which I had previously been unable to learn very much. I had run into many folks who assumed that one would never fire a valuable, non-reproduction antique pistol. That may be good for them--their pistol, their choice. But I could not dream of ever buying such a pistol if I thought I could never fire it.
This thread has been great. Many knowledgeable folks have offered the benefit of their experience. I am, and other readers are, now convinced that one can, in fact, safely shoot an antique pistol that is in good condition, provided one has carefully checked out mechanical condition in advance, one uses a cautious and gradual approach of increasing maximum pressure, and the pistol is initially fired, during the testing protocol, utilizing "a wooden fixture to hold the gun so you can pull the trigger remotely with a line."
Many thanks to all who offered such useful advice!