Yes,if that is the case,the good news is that with a better rank and try to improve the quality of his post, surely he will be accepted in any signature campaign later.
I think we can not guarantee someone could get in the signature campaign, because the opinion of the people are different. Accounts do you think it was good but not necessarily good according to campaign manager. But I think if the account has a history of great posts likely to be accepted. IMO
Even I wished to say same thing. We can maintain proper post with relevant to the above post which you are quoting and we should maintain long time to give a each post.
These kind of posts quality will make you to get accept in the campaigns.