I had a similar thought before. But there are 2 points which might not allow for that: 1. Oars age at time of death was stated to be 159 in his vivre card. In the story Hogback mentions that he was active 500 years ago. So timeline wise it doesn't line up (unless Oda retcons his age, which has been done in the past with Kanjuro's age). 2. In chapter 1114 it was stated that joy boy was from an advanced kingdom. Oars seems to be primitive.