Thanks Bounty!They're not all the same, per se. You want to find one with the same axle ratio as your truck.
If you're going to tune the used ECM then don't worry about year, 14-19. If you're going to use the used ECM as a stock ECM then you want to stick with 14-15 and 16-19, depending on the year of your truck. This is due to the use of a DEF quality sensor beginning in'16.