I saw this had been answered – but started thinking about how I would have found the info.
The best starting place would be the Detail Spec – if the airlines had them since new it’s relatively unlikely they would have changed from the “as delivered spec” – so your answer combined with extracts from the Detail Spec should be OK.
A quick check of the SB Status should confirm if any changes were made – and obviously a check against the EO list just in case they did an “in house mod”.
OK – before I get shouted at – the latter (in house) is unlikely – but not unknown – you’d be surprised at what some airlines belive they can do.