That seems to be the case, yes, so GGUs and advance upgrades are basically not available but upgrades seem to be easier than usual with lighter loads. It's largely because they are basically blocking half of the seats in the cabin, unless there are flyers traveling together, for social distancing. While F prices are significantly lower than in the past (it seems they're making more I fares available to compensate a bit/perhaps encourage more revenue from folks willing to buy F), another option is to use miles to confirm in F..