"Chronometre Quality" as used in the German book that Doc referenced many years ago, does not have a specific/exact definition. I understand it to be that those calibres were either:
1. at least one movement of that calibre was specifically regulated, tested, and passed Chronometer standards (i.e. sent to an Observatory and successfully passed the time trials) or
2. these were calibres that VC believed could pass Observatory time trials if regulated properly for that type of difficult testing.
The Geneva Seal standards are related to the quality of the movement, its construction, and appearance. The Geneva Seal requirements did not include a time-keeping accuracy standard until just a few years ago (in 2008, when the changes occurred with the creation of TimeLab, an new organization that manages both Geneva Seal and Cnronometer standards...from COSC to a newly developed Chronometric+ Observatory Certification).
Alex has shared with us in the past that for many decades, VC did not believe the Geneva Seal was a priority and so did not require all of its movements to have the Geneva Seal. Mnay of the classic, vintage calibres (i.e. 453, 454, 1003, etc.) could all meet the requirements for the Geneva Seal, but VC did not send each movement in for certification. They would do it if a customer specifically asked for it.
I do not believe there would have been a big price difference. But I guess if a customer specifically requested a GS, they would pay for any registration fee.