In download mode I do not have the Knox warranty void line...
Short answer...Do NOT flash that file. You'll have a fancy paperweight. You said you took the 4.3 OTA update meaning your custom rom and Knox apps removal has ZERO effect on the 4.3 KNOXED bootloader you have.
The 4.3 stock tar is here::[ROM][TAR] Stock MK3 Odin flashable