We can only conjecture at this point. IIRC, HT said they made 2000 of the Demon Bats/Scarecrow 2-pack, which they said was 1/4 of what they made for their previous Bats, which I believe we determined was the first TDK Bats, which puts that original version at 8000 pcs.
My educated guess on this DX Indy is 4000-5000 pcs. Honestly though, it's very hard to tell what their edition sizes are. Considering how tight their QC is, I think their runs are much smaller than people think.
why dont they just number them? it would be a good piece of marketing and the fan boys could wet themselves over high and low numbers