You are correct. CDs does not need the grade 1 symbol indicator because CD is not standing alone any more with the s after it (2.6). It does, however, require the capitals terminator before the s because the capital word indicator carries through letters unless it is explicitly stopped (8.4.1).
That said, CD's is the opposite. Now a grade 1 symbol (not word) (10.9.5) indicator is needed because CD is standing alone (2.6.4). The apostrophe stops capitals mode (8.4.2) so a capitals terminator is not needed.
- This reply was modified 6 years, 3 months ago by Julie Sumwalt.