The man you need to speak with is Harley Collins. Basically, I am told he knows about everything about Worthington's, has written a book about them.
I have a G-6 with a Continental 162 in it, waiting to be restored along with a Toro Allen Tractor '39 Bullet. The picture that i have is the dump unit, and mine is the bullet like the two you have. Bullets were built to pull gang mowers and some had rear/underbelly sickle mowers. Looking at a G-5 that has a flail mower in front.
Email me at email@example.com and I will send you Harley's address.