Nice,
In NY I have never heard of them being stocked. They only way you find them is as natives...
They are native to one of the local streams I fish in my home town. Since they are non-reproducing what that really means is that they are naturally occuring crosses between the native brookies and the stocked browns that live in the stream. (This usual occurs for only so long until the brookies are natural wiped out...That is why it is so rare for the tiger trout to truly occur natural. For that to happen the brookies have to have some unusual edge in that particular stream to hold out against the invasion of the dominant and more aggressive brookies...)
JC