2x 2Sk170 in place of 2SK389 and 2x 2SJ74 in place of 2SJ109?

[Regenpak]

I still don't understand why, on the 389, the gate of one side reacts -
multimeter in diode test - with the drain/source of opposite side....

Might be the substrate of the chip. Depends on how it's manufactured but I don't believe these devices contain two physical chips.