I’d try to contact the artist and ask. As you can tell from these forums, clay people are very generous and, from my own experience, are almost always happy to share and help out. Good luck!
The first photo does look like gold luster, but I don’t think it’s ever red when applied. Although you might achieve the same results with luster.
oops - my mistake! I wasn’t aware that gold lustre could have a red brushing medium. My apologies!