1972 duster original a/c

I have all the interior parts of course need to rebuild everything , but nothing under hood all missing , question is it worth finding an putting back to mostly factory setup or go after market ? I can do all the work including charging with freon , just looking at cost , I would have to rebuild my heater/a/c box and buy all parts under hood to put back to original which is condenser , pump an all lines an fittings, dryer ,,I would need to buy some things even with a classic air conversion plus I need the box working for heat inside anyways ,,just looking for suggestions on a good path