From what I recall people who asked back in 2017 after we knew the races were cancelled for 2018 and would return "at a future date" were told Legacy would be honored. But it was never stated in writing online so never really official official.
Honestly? I wouldn't be surprised if they were thinking of not offering it since it makes it less of an incentive to buy CrD when available (and they already took away AP/DVC early reg which I'm still salty about). But maybe someone spoke up and said it would be poorly received if they didn't offer it? Since Legacy is still a thing for WDW races and there were Legacy for DLR races it would be low even for Disney to remove that acknowledgement and the perk that comes with it.
And yeah, that does set the precedent for races that already acknowledged Legacy so here's hoping! I'm also hoping if Tink returns that PDC returns with it and gets Legacy status when it reaches its 5th year

. We only got through 3 PDCs, though, so we'll see.