Jimmy Fu used his own 'C' (or possibly 'D') series watch for his project, so his cases were 1:1 copies of that series. However, since 1997 Panerai had become part of the Vendome Group (now Richemont, S.A.) and, for the pre-A had used the remaining OP stock of 400 cases, together with 600 of their own production, so the pre-A utilised cases from both companies’ manufacture.
While there were two, separate series of the 1000 pre-A watches, during 1997, the OP 6500 (500+) and the OP 6502, I haven’t noted any record of visible case differences during that period. Given that there were only 400 Luminor cases inherited from the preVendome OP and 600 ‘new’ cases, it follows that, at least some of the 500+ first series (OP 6500) must have been the newer production. Then, particularly as it was anticipated that Panerai would only ever be a low volume, niche brand, it is highly unlikely that, having tooled up for production of the first 600 Vendome cases, that the design would have altered for the next few years' low volume runs. Therefore, unless there is any evidence to the contrary I would conclude that they are identical.