Yes, I think your version is correct, but I'd do it like this:
Code:
_EAXOBSTRUCTIONPROPERTIES = record
  lObstruction: int64;
  flObstruction: single;
end;
EAXOBSTRUCTIONPROPERTIES = _EAXOBSTRUCTIONPROPERTIES;
LPEAXOBSTRUCTIONPROPERTIES = ^EAXOBSTRUCTIONPROPERTIES;
Similar to what you can find in Windows.pas.