Brian,
This whole discussion of the bronzes is very interesting. I am lucky enough to have a copy of the American Society of Metals Handbook, so I tried a little research. First, I wonder if the bar you got is cast or wrought. In castings, it appears that the name for 85-5-5-5 is "Leaded Red Brass", while 83-7-7-3 is "High Lead Tin Bronze".
The following paragraphs in the sleeve bearing section were interesting:
TIN BRONZES
The bearing bronzes are substantially alloys of copper, with from 5 to 20 % Sn, and a small percentage of residual phosphorus - phosphorus remaining after deoxidation of the alloys with 10 to 15% phosphor copper. These alloys are sometimes referred to as "phosphor bronzes".
When 2 to 6% Zn is used instead of of phosphorus, the alloy is quite generally referred to as "gun metal" (also, as Government bronze, composition G, admiralty bronze, or zinc bronze).
I don't know if any of this is news to you, but it was interesting to me in following the thread of your topic.
Richard L.