I just got this offer on the receipt from my shop and also saw this offer displayed instore (so not a targeted offer). As my receipt is not a flybuys scanned one, I think it is a generic same barcode (can be confirmed by others here soon). It may not look like a great percentage rebate, but you can stack with any targeted offers you are with this week. I think any receipts from today till Tuesday will have this offer on them. However, you certainly do not want to know about it after you already finish your shop.
So essentially, it is free 1000 bonus points for someone is doing 4 weeks shop in Coles now. You can even plan to use it from the coming Monday for 2nd week shop.