That is most definitely not what that means. Jiren had the power, a lot more than Goku, necessary to force the spirit bomb back towards Goku. That's quite a bit different from actually being hit with the attack and sustaining direct damage from it. As the other poster said, Jiren made sure he was never hit by it. That said, presumably if Goku could take it like he did, then there's ample reason to think that Jiren could also. Frieza also took a direct hit from a spirit bomb once before as well.
It's entirely possible that Jiren could have so much power that even the spirit bomb wouldn't hurt him much. So what you say is likely, but we have to remember he was never actually hit by the attack.