Second the motion that an AAR 620 won't do. Mine won't attach properly to my 2x3 Graflex (SLR, not a Graphic press camera) that has a Graflex back.
Re Graflex-made roll holders to fit Graflex SLRs, look here: http://www.cameraeccentric.com/html/info/graflex_1.html . I have two of 'em, of which one will attach properly to Graflex and Graflok backs and one will attach only to Graflex backs. It seems that the type that works on both backs was made for only a short while.
Thanks for the photo of your treasure. A shot of one of the gates with the film holder removed would be very useful.