Not necessarily.
The AG-42 and 42b used the same gas system (no difference other than one being stainless and one not). The rear sight is actually calibrated for both calibers, there is a little spring steel wire behind the dial, which you can pull out and turn the dial until it goes from pointed to round nose if you so choose.
Personally I would use 140grns myself and start at the bare minimum loading moving up slowly until I had something the rifle functioned with but wasn't shooting brass to the next range.
In service because the gas system was set up to overgas the rifle they would oil cartridges to assist in reliability as it was simply overgassed so much. Don't oil the cartridges yourself, that is dangerous, just stating what they would do. Whether or not the overgassing was a symptom of being developed in about 9 months or just deciding it was better to have too much gas than too little, I don't know.
The other thing is with reloading for them DO NOT USE FEDERAL PRIMERS. They are too sensitive and will lead to a out of battery detonation, I know this from personal experience.