No, you can only redeem the guaranteed trade-in value for the new iPhone you bought together with Bring it Back.
Your new iPhone needs to be in good condition when trading it in (i.e., no cosmetic or screen damage, sharp and clear display, phone is factory reset).
Your new iPhone’s IMEI should also match with the model you bought 12 months earlier. If you’ve exchanged your device before trade-in, you should keep your proof of exchange so you can still redeem your Bring it Back trade-in value.