This is one note that I believe is under valued it has the same amount printed as I/O and D/O all having (80,000) printed but is worth $150 in unc. while D/O is $200 and I/O is $375.
It seems to me that the N/Y is seen as rarely as the I/O and the D/O is seen more often.
It could be seen more often if the value was to go up,that may be what collectors are waiting for to part with them.
I think they should be valued about $250 - $300 in unc, this is one of those notes that can be purchased above book now and be a good deal when the next catalogue comes out.