They are all-Americans, just ask AP

For years -- no, decades -- I've worked to great frustration to remind people that in the Associated Press Stylebook, the "All-America" entry refers ONLY to the AP All-America teams.

In doing some other searching in the digital AP Stylebook, I find the definitive answer:

In AP stories, AP limits the All-America (capitalized) designation to the Walter Camp and AP selections. Depending on the context, AP might report that an individual was all-American (first "a" lowercase) on another roster. Other news organizations are of course free to follow their own guidelines.

The bold and underline, obviously, are my emphasis.  That is a 2007 interpretation.  A more recent 2011 reinforces:

Webster's includes a hypothetical football team as one definition of all-American. Evidently it is not referring specifically to AP's All-America football and basketball selections, which cap both A's in this formal name.

While the editor is being a little cheeky (see the "evidently it is not referring specifically to AP's All-America" and thus insinuating that Webster's would OBVIOUSLY use "All-American" only if it was the AP team), it provides us another reinforcement.  When it is a trademark name, cap the A in all.  Just like CoSIDA's Academic All-America team -- because "Academic All-America" is a trademark of CoSIDA.  An interesting fact overlooked in an AP Stylebook entry that said you do cap all three "A"s.

If you want to read my lengthy treatise on why all-American is the right way to speak in the generic versus All-American, jump here.

Or, you can just take my word (and AP's) for it.