I think they could probably do significantly faster than that since these would presumably be a relatively low volume, single customer application, and wouldn't need the extensive testing cycle required for mass production ASICs. Which is to say it doesn't take a year from delivering a mask set to a fab to getting packaged parts.

Gate arrays can be pumped out in weeks to days if you control the fab.

That's not true at all. Were you paying attention to the development of bitcoin asics? Those things popped up fast once the idea spread.