They're all the same. I got an Oreilly's one cause it's a lifetime warranty.
Your truck probably has green and maybe gold coolant, and may or may not have had the SCAs kept in check. There are also many silicates from the gold coolant and just from the sand cast block itself that can eat up the system. SCAs not maintained can lead to cavitation and major problems. An ELC that is CAT EC-1 rated has no silicates and SCAs already included. Maint free for at least 300k miles. The 203* thermo is the original thermo from IH, which made the motor as we all know. The billet housing is tougher and won't break/warp/crap out like the OEM one. The coolant filter will keep the system clean, which it needs.
You can search for all this stuff. You don't NEED to do this but since it'll be apart and drained, might as well at least flush it and change to ELC.