Copper Tracks being gold plated

Most people would use nickel/gold plated on top of the copper tracks on the PCBs, by doing so, resistance may get higher. As you know copper is already the second best metal for transmission of electrons besides silver. Gold is even having higher resistance than copper, the only merit for plating gold is to shield up the copper from getting oxidized.

That's why I would suggest applying hot air tin solder leveling on top of the copper pad to the PCBs which will further prevent copper from being oxidized and ensure secure connection of components on all pads while you can save up some cost as well.