The following is guess-work:
Deckel toolchanger machines from the FP NC series were available from about 1984. Only the FP4NC was available with toolchanger initially. The toolchanger had a round plexiglas enclosure. For automatic operations the chip enclosure had additional safety switches, so the machine would stop if someone opened the doors.
Toolchanger machines did not have quills. Pictures showing otherwise must have been of prototypes. Only the vertical spindle was loaded.
This early type was the FP4TC. It was probably only available with Dialog 3 or Siemens 3M. Possibly very briefly also with Dialog 4.
Later the "A" NC series came on the market. These machines were the FP3ATC and the FP4ATC and had Contour 3 controls. These machines were overlapped timewise by the FP4AT, which came later and had a Dialog 11 control.
Only the "A" machines were available with toolchangers, because the toolchanger was never combined with the high speed flip head of the non-"A" machines.
On the A-machines the toolchanger was much more integrated into the machine through use of sheet metal housings.
While the "TC" machines had a massive steel subplate connecting the toolchanger and the machine, the "A" machines had the toolchanger bolted to the side.
By todays standards the tool change time was very slow and the toolchanger is known for being somewhat unreliable and not without problems. Supposedly there were also some software problems on some later machines, which are rumored to never have gotten really resolved, resulting in tools being dropped.
The author has no first hand experience though.
A very nice picture from the 1984 sales brochure:
A look into a later style tool changer:
2 nice pictures of the impressive FP5CC/T with pallet changer:
The tool changer head is very different from the regular one. Note the bearing lay out: