The information that I have received from Siemens on this matter is as follows: (a letter from UL)
The suitability of circuit breakers manufactured by Siemens Energy & Automation, Inc. for use in panelboards and other products manufactured by I-T-E, Gould or Siemens-Allis may be questioned because the markings on those products do not reference circuit breakers manufactured by Siemens Energy & Automation, Inc.
Siemens Energy & Automation, Inc. circuit breakers of the same Type designation that are referenced by the marking on the panelboards and other products are the same as the original Type designation circuit breakers manufactured by I-T-E, Gould, or Siemens-Allis. Therefore, in field installations, circuit breakers bearing the Siemens Energy & Automation, Inc. name are suitable for installation and replacement of the same Type designation circuit breakers with the I-T-E, Gould or Siemens-Allis name in I-T-E, Gould or Siemens-Allis panelboards and other products. I hope this helps.