I see in the EPC that inside ones PN starts with 113, outside with 115 (one part number for both sides for outside). Outside one was used in W 113, 114 and 115.
Inside is for W113 only as per the EPC.
The outside one, PN A 115 910 09 05 replaced an earlier one, PN A 113 910 05 05 - just to note.
This is theory, not a practical knowledge...