No - However, make sure you have at least 10 hubs published as that is considered your content. The same rules apply with adsense and hubpages as they would apply if you were applying for adsense with your own site.
You need to have content before you apply. Another thing to keep in mind though is that the more you write the higher your hubscore will be. If you have applied and been rejected recently, that is probably because you don't have enough content. Keep in mind that you apply with your subdomain, example.hubpages.com, and google looks at what you have on it. Hope I answered your question clearly and informatively.