Can I upgrade an Enrich redemption using a cash upgrade offer?

I have enough Enrich points to redeem an economy fare from KL to Mel later in the year which would come in really handy as i am flying the other way with SG.

The booking class is L which i think is an upgrade able class if available do you think i will still be emailed one of their paid upgrade offers to business on a redemption booking?

It’s technically miles plus cash as i am a few miles short and will have to chip in about $30 plus the taxes.

Any answers would be great my flight could have left by the time i wait in their phone queue and the girls never sound confident with their answers.