I never heard of this company before, but it looks like they are legit from what I saw.
However, the motherboard that is part of the bundle is just listed as a "AMD A320-MB". I can't see from the pic who the manufacturer is, but adding a Ryzen 2700X and the Asrock A320M-HDV at Newegg (which is the motherboard it looks like Portatech is using, but they removed the "Asrock" from the heatsink for whatever reason) comes to almost roughly the same price ($369.98).