The suit worn by the Apollo Command Module Pilot CMP suit differs most visibly from the one worn by the Commander (CDR) and Lunar Module Pilot (LMP) in that the CMP suit sports a single set of life support connectors; this is because the CMP is only ever hooked up to the command module's life support system. The CDR and LMP have two sets of connectors on their suits because they need to be simultaneously hooked up to the lunar module life support system and their portable life support system (PLSS). Less visibly, the CMP suit was covered with an "intravehicular cover layer" (IVCL) rather than an integrated thermal mecrometeoroid garment (ITMG): Since the CMP would not perform a lunar surface EVA, the suit's cover layer did not have to provide the extra protective layers required for extravehicular activity.

The Apollo Experience Report: Development of the Extravehicular Mobility Unit has additional information on both the A7L and A7LB suits.

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From p. 75a (p 100 in the PDF) of the Apollo 8 Press Kit [direct link to 4.3 meg PDF] from the heroicrelics mirror of the Kennedy Space Center Library press kit page.
Extraction and cleanup by heroicrelics.