I really doubt it. For one, the steam page just says 15th because they had to pick a date. In fact I just checked and it doesn't say that anymore, it just says "Winter 2019" which really means "Q1 2019". Also, I'm only sure they consider the textures good enough to show off, but that doesn't necessarily mean it's fully finalized. There'll probably be a few more quality passes before release. Heatblur will let us know when they are sure about the release date.