I'm now 100% convinced that its Hilltop Park. However, check out the pictures below, as well as the numerous others on Flickr. Every one of them is said to be from 1912. But I cannot find a single one among them that shows the Wayne Knit Hoisery ad. Which leads me to suspect one of two things ...
1. They changed the ad displays periodically during the 1912 season.
or
2. The photo was not actually taken in 1912 but is from some other year.
* If you click around enough you will see every part of the outfield walls - left - center - and right. Of course, were are only concerned with the right field wall. The link shows about 100 similar photos.
Link:
http://www.flickr.com/search/?q=hill...%201912#page=0