Pretty bizarre reply, but I assume a misunderstanding and your not screwing with me... first it is Amberg as on the receiver, second it's 15 recorded examples over 20 years of collecting data on the subject (basically 1997 through 2022 or so- I have loads of unprocessed data but stopped in 2020-2022 incorporating reports into trends.
Anyway, each block is roughly 10,000 rifles, the Amberg/1914 is solidly confirmed to the mid-c block with a supported pattern to the early d-block, a simple calculation:
No suffix = roughly 10k
a-block = roughly 20k
etc.. to the known high 581/d which is not solidly confirmed but is supported by several rifles between the "solid" confirmed rifle and the d-block(in other words it is a safe probability 581/d is valid.
*** in short Amberg/14 is a rather rare rifle, far rarer still in upper grades (original Imperial matching especially) but that only 15 have been observed(by me, clearly others may have seen more but many do not post to forums, a good buddy and sharpe long timer I know only lurks, similar to Jon Speed, and it is rare that the best researchers fart out years of research on the internet for every arse to critique...)