I have every model of the single and double Bear Spring Arm Quivers, including some experimental and prototypes.
Years ago, I used and tested the various double spring arms on various bows of their period. As my Father always said, experience is the price of an education.
For me, single spring arm Bear Quivers with the stabilizer hole brackets are much nicer in every regard when compared to the double spring arms.
Once you find the stabilizer hole brackets you can use them on other vintage Bears you acquire later.
The effort and expense to locate the brackets is well worth whatever it costs in time and money.