The N jfets often had a large spread of Idss and gfs and other parameters within the same part number.
For example I use 2n4416 (nos surplus, NF 2.0 dB ) like that and can adjust Rs if necessary for hobby use...
2N5670:
Looking at data sheet from New Jersey Semi,
It is in a group had a low noise figure of 2.5 dB compared to the more usual 4dB
it seems there were 3 part numbers splitting Vp and Idss
2n5668, igss 1 to 5 mA; 2n5669, igss 4 to 10 mA; 2n5670, igss 8 to 20 mA;
And Vp went 0.2, 1.0, 2.0 V over those 3 parts.
The above may be of assistance if you decide (reluctantly) to give up search and seek alternative.