I would regard and handle this as a company secret, as Jolla does with the number of sold SailfishOS licenses ("SailfishX") and the number of active devices accessing the Jolla Store.

Any published number will generate more critical comments:
- Oh, so few! Is this project really feasible, then?
- Oh, so many. But why am I not among the first batch, then!

And while the first batch comprises a specific number of assembled devices, things can go wrong as it is the first mass production run, so F(x)tec may receive far less working devices.
Hence even they do not know how many "first batch" devices will be available.

Why does this number appear to be relevant for you?