The Automatic Float Deployment System (AFDS) has been flying on the Super Puma series since 1996, it was around for about a year or so earlier on a limited number of aircraft while under development.
It was a Bristow development which was I think designed after a previous 332 accident whilst shuttling between rigs in bad weather, has been certified for the 332L/L1/L2 & EC225 series and is available for the S76 series. The system is I understand available to be fitted by Eurocopter and Sikorsky if a customer requests it, or as an aftermarket solution from Bristow.
To follow on from Malabo; as far as I know it has an inbuilt time delay to ensure energy attenuation prior to deployment of the floats to prevent them being ripped from the aircraft if they inflate too early.
Who knows if they were deployed by the crew or by the automatic system (be interesting to find out) but by all the evidence it does appear that they deployed correctly by whichever method and were effective in preventing a total catastrophe.