The 1988 repro set needs O-72.
Also, beware of paint "bubbling" issues, especially on the engine. I suggest asking specifically about this problem.
There are several copies of this set on eBay right now - some appear to be bargains, others not so much. This set can usually be found at meets with asking price of $300-400 NIB. One ebay seller has it for over $1100 with "some paint loss"; they don't list the item number, and list the year as 1957, even though one of the pics shows the set in the foam insert. Misleading???
Good luck. It's a beautiful set.