I never knew the exact number, though I also heard the total was around 40 for the anniversary 5089G's, and they made quite a few versions. The catalogue I have says "limited edition" for most versions (including the four of this series), while a few it has them as "unique pieces" (e.g., the 5089G-001, -010, -011, or -012)... So the limited series are likely to carry at most 4 to 6 pieces each, but I'd be quite curious too to know the exact number... Perhaps Gordon has the answer? 
Best wishes