That is not how it was originally conceived but the answer is “yes”. 
The champion is the person who advocates for your product within the target customer “organization”. They are the propulsion engine required to overcome the inertia so that an acquisition process is started and a decision is made.
The original way it was conceived (at least by me) was that is was someone inside the organization. In a B2B example, they are an employee in the target customer organization that you can point to on an organization chart.
If someone was from outside of the organization, they were by default into the “influencer” category. There is a difference between the two but it is not big. When I first wrote the book, I considered champions internally only and they were the “propulsion” as opposed to the smaller force of an influencer. Influencers can be external or internal but they just have a lower direct force in the process. They are passive.
Today, as organizations have become more fluid and boundaries are less rigid, I have updated my thoughts and believe that a champion could come from outside as well. Government can now be a champion and not just a veto classification. Advocacy groups can do this as well. The difference is that they are an active force but not a requirement. Once it becomes a requirement, I would no longer classify it as a “champion”. That is most often even better for the sales process.
These differences may not seem to matter but I would argue having a discussion about them is valuable as it give you and your team a better understanding of the acquisition (or sales) process with is always good.

Thank you very much Bill for the thorough answer. 

Hi Maria – yes, as Bill clarified the external ‘champion’ is an influencer –
And the other related concept is the lighthouse customer – the one(s) who will tell others about your product – they are often influencers, early adopters or ‘thought leaders’. So it’s good to think about who are your ideal lighthouse customers and how connected are they to the target customer base…
A few years ago, I was selected to be an electric car ‘ambassador’, showing off the capabilities of EVs through videos, blog posts, articles, etc. – who would be your ideal product ambassadors? They may not have the exact same persona as your broader customer base but they should certainly have an impact!
John.