From SQ's FAQ:
I've made a booking before 20 January 2018 but will not ticket it until after. Can I still enjoy the old fare conditions?
Tickets issued before 20 January 2018 will be subject to the old fare conditions, while tickets issued on or after 20 January 2018 will be based on the new fare conditions. This means that if you only ticket your booking after 20 January 2018, the new fare conditions will apply.
So the question is this, are points and SC part of the fare conditions.
Edit: Maybe I should of read further down the FAQ page.
Will the new mileage accrual rates affect tickets I've already purchased?
If your ticket was issued or you make changes to your booking before 20 January 2018, the old mileage accrual rates apply. If your ticket is issued or you make changes to your booking on or after 20 January 2018, the new mileage accrual rates apply. The old mileage accrual rates will continue to apply to your unchanged sector(s).