Yes. Pre '84 cars had a system similar to the 365GT 2+2 and 365GT4 2+2. They have oen coil-over shock and one "pump up" style load leveler on each side. No cam driven pump or leveling valve. I'm pretty sure that if you have the hydraulic pump, then all 4 of your rear shocks should look the same? 4 hydraulic coil-overs.
Mercedes and Ferrari did indeed use the same load levelers. The one difference between them is the placement of the fitment brackets. You can knock of the M/B brackets and tack weld your Ferrari brackets.I hope that this is of some help to someone. Jq.