Yeah that’s in quotes too like they got it from him or his posts announcing these. I’d say it’s a typo which he is really good at.

.999 silver is common phrase to put on rounds but can be referred to as 99.9% too so someone probably typed it up wrong and combined them.

I would question the purity too though until I see them tested properly. There are other companies making clad Trump rounds and trying to sell them as high value collectibles especially gold plated ones.