Base Power doesn't get affected by STAB. But if you take it literally, yeah, the final damage would be 315.

**Facade Base Power**: 70

**STAB Bonus** : x 1.5

**Guts Bonus** : x 1.5

**Facade's power would double itself if inflicted by status**

So, the final power would be:

*70 x 1.5 x 1.5 x 2 = 315*.

But as Fizz said, Damage Calculation doesn't work precisely this way. This is just an estimation. Stab Bonus doesn't affect the power but the effect is basically the same. Also other modifiers affect this. So, excluding STAB,

*70 x 1.5 x 2 = 210*

Hope this helps :)