Just out of curiousity, I’d like to know your Invoice Nos.
My A whistle is No.1124. 
Bb is No.1331.
hmm I wonder how many whistles a whistle maker is supposed to make in one’s lifetime…heh.
Mine are yet to be made, but my invoice number is 1616 (ordered last year in May).
My A whistle was shipped 2-4-2003,
the number has been increasing like that as you showed us.
I see. Thanks. 
You’re assuming that’s one whistle per invoice. When I ordered 5 whistles I only had 1 invoice number.
I took what you pointed out into consideration,so what I tried to know was not the accurate number.
Anyway good to know that, thanks.