The minimum requirements for CPU and GPU are i3 4340, FX-6300 and GTX 660 2GB, HD7580 2GB.
So no, that spec is below minimum. The RX 460 will play it on very low settings since it's only slightly less powerful than the minimum required 7580, but the a8 3870k is barely more than half as powerful as the minimum required FX-6300.
PUBG is not the type of game you want to try playing on lowest settings, especially with a very weak CPU. The GPU would handle some parts of it, others with lots of lag and stutter. The weak CPU makes it a definite deal breaker though.