If your application is Motif 2.1 style guide-compliant, you are well on your way to it being CDE style guide-compliant. Solaris Motif is based on the Motif 2.1 toolkit and the CDE style guide is based on the Motif 2.1 style guide. Still, you may have to make some GUI changes to port your application to Solaris Motif.
To help port your Motif application to the Solaris CDE desktop, read:
Chapter 3, Solaris Motif Toolkits, to find out about the enhancements in Solaris Motif and the CDE widgets available to you
Chapter 4, Development Environment Transition Issues, which compares and contrasts the OpenWindows and Solaris CDE development environments
Refer to the checklist in the Common Desktop Environment: Style Guide and Certification Checklist to see how the CDE style guidelines are similar to and differ from those for Motif 1.2.