Agreed! I'm guessing it's to have them in line with the gun tubes inside the wheel bays, but I would have thought a company like Tamiya would have been able to sort the moulding tools to allow separate barrels; there's enough room to fit them into the leading edge of the wing, after all.
Even though the kit dates back to 1995, and overall is quite nice, I personally don't think it's quite up to Tamiya's high standard.