I don't have a TX-1000, but I do have a beautiful TX-2000 complete with the original walnut cabinet.
Both are listed as 50 wpc RMS, freq. response 20Hz-40kHz +/- 1.5 dB, THD 0.5%.
Front panel controls appear to be identical based on catalog pics. The 1000 appears in the 1968 Handbook, and the 2000 in the 1973. The 1000 had full-page exposure, but by 1973 Quad, receivers, and combo units were big, and the integrated amps were in the back, in very small ads.