Lots of interesting theories here.
Why would it? If nobody knew of it and Rocks had Dragon before he gained fame nobody would be looking for his son.
I was thinking maybe there is a reason why Roger went into length to trust and chose Garb to protect Ace from the Navy when they were hunting all the pregnant women.
Given that they fought together in God Valley, Roger saw Garb took Dragon with him because Xebec in his dying state said so then Garb felt ashamed and agreed to do so.
He took Dragon with him to East Blue, trained him so he could become a marine while young Dadan sheltered him.
Until the Ohara incident 2 years later changed him as seen in chapter 1065 and that’s the Revolutionary was formed.
This would be very fitting for Garb who raised and trained the 3 to become marines but failed and they all ended up in the most wanted list.
I like to think so but as some pointed he was 17 at that time so it can’t be :(