Okay - your 8-12 is a fairly early example... mine is in the 5000 serial block, although it is a VE, not a VV... not sure how that skews dating... the paper label on the cabinet bottom is dated Sept 1927, if I remember correctly.
If you look on the bottom of the cabinet, you might find a paper label, a little smaller than a 3x5 index card with the user license information. At the bottom-left, near the edge is usually a printing date for the label. These dates usually are within month or so of the machine's final assembly.
Also, I see yours has the needle-type speed indicator, another indicator of earlier production; later machines had no indicator, just an oval escutcheon and thumb-screw, similar to a VV-VI.
Very late machines had a "three-eared" crank escutcheon, with three screws.
A good friend has two 8-12's, one from forum member "Gemering", and they both sound quite fine.
By comparison, my great-grandmother's machine sounds a little anemic, so I will probably goo looking for leaks in the horn / plumbing when warm weather returns.
Eventually, I will get my 2-door Credenza running, and will so some "Tone-Tests" comparing the 8-12 and the Credenza.
My friend with the other two 8-12's is an electrical engineer by trade, and has a very good ear... we have talked about taking a day or two, getting all our Orthophonics in the same room, and doing a series of recordings, sampling and comparing each machine, using the same record, reproducer, recording set-up, etc.
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