The Puch moped headset cups and threaded cone should work, they look to have the very same 14-ball retainers and thin pressed cups.
Even the threaded cone looks the same to me.
Mopeds often use a triple-clamp style fork, so the locknut isn't so much part of the headset I guess?

I believe that if you use Loctite on clean threads, that both the threaded cone and locknut will absolutely stay tight.

I've raced many seasons on a bike with the threaded cone Loctited so I could lower the stem fully down to the steerer (cut flush with the threaded cone), and it has never loosened.
I've also repaired MTB race bikes for others that had the steerer threads looking torn off by a damaged die, and with Loctite the repair held up to extremely hard service indefinitely.

High-end bikes are the first ones to be updated on a factory's assembly lines, while lower-spec models may persist with old-standard geometry and dimensions, including threading, for many years.
The high-end bike needs to be compatible with contemporary high-end parts after all, whereas the lower model's components were more likely in-house made or locally sourced in those days.