Sorry to hop on this thread but wanted to discuss the topic of upgrades. In OP's case the 'upgrade' isn't a true upgrade since it is an equipment switch and the first-class seats are sold as business class.

I was wondering if anyone knows whether JAL actually upgrades elites? I've been JGCP for two years and currently Sapphire and flown frequently (>20 times in past year) on Y tickets. Never have I been upgraded or an upgrade even mentioned at the airport check-in counter. I do get emails asking to bid to upgrade though. On some flights it is clear that the J or PY cabins have significant vacancy. This is in huge contrast to airlines in America that upgrade elites at the gate to fill their premium seats. On long international flights, there would be an understandable difference in cost of service but even for Japan domestic flights, I have not been offered upgrades (to class J, for example, which has no service upgrade other than a slightly larger seat).

I don't think anyone "deserves an upgrade" and I am perfectly happy to travel in whatever class I have booked in, but it just seems that JAL policy is different to a lot of other airlines. Even putting aside American carriers, ANA offers upgrade vouchers to their elites and I heard a lot of cases of CX upgrading their elites. JAL is also very restrictive in allowing mileage upgrades - most fares are ineligible.