Ernie Root made his bows, to the best of my knowledge, from the early 50's to the late 60's/early 70's in Grand Rapids, MI. At some point around the late 60's he sold a number of his designs to Shakespear, who in turn slimmed them down and renamed them. For example: The Brush-Master became the Neceedah, and the Game-Master was altered into the Ocala and the Kaibab. The first bows of this type bore the name "Root, by Shakespear". Shortly thereafter Ernie root went to work for Shakespear, and the Root name was dropped completely. The Shakespears were servicable bows, but IMO not near the quality of the Roots, and I've owned examples of both.

His early bows were rather basic, but standard for the time--straight grips, narrow shelves, and plain woods. I've seen Game-Masters, Field-Masters, and Target-Masters in the early designs.

Around the early 60's his bows started to resemble what we now see in one-piece recurves, They had contoured grips, exotic woods, and more artistry in the higher-end models--the Game-Master and the Pendulus Supreme.

If your friend's Field-Master has a longbow-type grip and a slim riser, it's an early model. If the grip is more contoured--like a modern one-piece bow, then it's a 60's model.