My 2.0 TS 16v had A/C fitted right after delivery (new, as Christian U says, the DK tax system disfavor fitting before registration of a new car).
Part no. for the kit for a 155 TS 16v is/was 00059006120000 price € 1220.- + VAT.
My car had also a radio/CD changer, speakers, antenna modules, an alarm incorporated in the locking system and an engine heater incorporated in the heating and ventilation system of the car.
For all this work 33 hours was invoiced – my guess is that at least 20 hours went fitting the A/C.
It’s probably unlikely that the A/C kit is available now, but if you find a bend 155 with A/C it probably have to have the same engine family as yours, 4cyl 8V, 4cyl 16V, V6, 1,9 Diesel or 2,5 Diesel.
Hope this clears the A/C mysteries a little.
PS. My 155 have the electronic heating and ventilations controls which I think is necessary for the A/C.