No. JG gears are really strong. They are injection molded steel and not sintered like a lot of stock gears. Although not very precisely cast they are some of the strongest gears you can buy barring RiotSC of course. I'd be more concerned for the systema pinion. Do you already own the systema motor or are you buying one?
Systema pinion gears aren't that strong, considering the price they're shocking.
One thing to be aware of, is that when I put a Systema motor in my L85 I found that the angle of the teeth on the Systema pinion wasn't the same as the angle of the ICS bevel gear.
It wasn't down to adjustment, the angles just didn't fit right.
So I ended up chewing up two Systema pinions in around 40k rounds.