Hi Ben,
Short answer, not to my knowledge.
As I mentioned before, just adding a few frames might change the evaluation of the tracker quality. Since new data is available, the calculation of the previous might change. With that, the tracker used to set up orientation, size, and position, might not be useable anymore.
I have tried to recreate your set up. Copied the frames in a new folder and only a limited range, here with an image-sequence. The frames were labeled: name_sequencenumber_dot_suffix
The tracker recognized the numbers and set the range. Since the tracker has set this range, there is no given option to change that.
At the moment I added images to that folder, they are not recognized.
If I reload the footage, it deletes the solve. I assume for varies reasons.
If the footage is either based on a single file or as a sequence, but containing all frames, then the frame settings (Start/Stop) would have limited the number of frames (if adjusted), and it would have allowed to change it later on. However, it would solve the whole tracking newly, of course, and with that, the quality of the tracker might vary.
My best wishes for the project.