I received this beautiful brown key set this month, made in February 1958.
The model number would be 564HBR-54, I think, and perhaps then some letters for the key designations. It's a HPPPPP type, with pickup buttons for 5 lines, and one hold key.
Base: A/B 564H 2-58
Feet: nice brown leather
Housing: brown Tenite, 1 24 58 2
Handset: G3, brown Tenite, 1-58
RX: U1, 12-7-57, cap: 2-58, nch
TX: T1, 1 27 58, cap: 1-58, nch
Cord: H4BH II 57, brown thick coiled cord
Dial: 7C 54 1-58
Face plate: w/gasket
Finger wheel: Lucite, clear, open center
Dial center: cellulose acetate window, Bell System logo
Network: 425B 1-58
Ringer: C4A 2-58
key assembly 589H
Being of that age, all plastics are of the very smelly, "soft" Tenite of the 1950s sets.
It was a special find not only because of the color's rarity, but also because I recognized this telephone from a previous encounter, when it was auctioned in Cleveland with the remains of the AT&T museum in May of this year. The bidding then quickly went beyond my scope of interest. Yet here it came again...
Upon examination, it occurred to me that this telephone was perhaps never in active service, never installed at a paying customer location.
It has a special sticker on the bottom that appears to indicate that the phone was "distributed" by the public relations department of the Ohio Bell Telephone Company in Cleveland. Why would the PR department release phones? Well, for marketing and community purposes. The sticker has two check boxes "Lec. Dem." and "Disp'l.". The latter one clearly is for "display" purposes, and the former one, I can only guess, means "Local Exchange Carrier Demonstration unit", but the term LEC was probably not known yet at the time. The sticker has a serial number for tracking purpose, no doubt, as they expected these to be returned.
The set didn't come with the 30-conductor mounting cord, perhaps it's because it indeed was never installed and was only supposed to be a display item. Given that the unit came from Ohio Bell on Carnegie Street in Cleveland, and was found at the telephone museum in Cleveland, this telephone may very well have been given directly to the museum for display purposes.
It's nice when a telephone has a little story.