That's a Diamond "Professional", not the "Pro-Am". It comes completely apart like a GC and is 3 piece slate, so you can fit it anywhere. It was Diamond's main model before they came out with the Pro-Am. Its actually still available new today, with some updated corners and legs, and the leveling system introduced with the Pro-Am.
The black label doesn't mean anything. Years ago the standard label was red, but you could get black as an option. But it does not mean any specs are different. This table will play exactly like a red label table, unless the owner modified it over the years. It won't have the new wood angles that the Blue label signifies.
This table looks to have the solid oak rails, (real wood), and not the dynawood phenolic impregranted rails.
If you like the way older Diamond's play, this will be what you are used to. If you like the way GC's play, then this will be quite different.
I'm not a table mechanic for the record, just a pool enthusiast.