Here’s what it says about Silver benefits:

• a checked baggage allowance of two pieces in economy for everyone on your booking (except on hand baggage only (Basic) fares)*
• a weight allowance of 32kg (71lb) per checked bag in any travel class for everyone on your bookinG

*You must be travelling on the booking for the benefit to apply. Not available on group rate bookings.

It looks like you get the 32kg