I know this old, and granted none of these trucks were new except some 2014s every thing after 2014 were new at the time..
I've only done two 2003's one RC4x2 and the other QC4x4 , the 4x2 hit 281, the QC barely made 260.
Most of the bone stock 04-05s I've dynoed were 270-280.
06 -08, about 280-290, seams to be a better OEM tune.
09-10, mostly 305-310
11-14s 305-315 with the RFE(POS)65 ,8sp 315-320ish , , ..had one 8sp that did 329 last winter.
we had a 14 with a RFE65 late October last year that was a FREAK, laid down 322, rubbed my bald head for about 30 mins trying to figure that one out, Pulled the tune compared it to a few other 2014 files I have....dam thing was bone stock.
15+ seem to hover around 320s
All done here on the east coast, shop elevation is 570FT above sea level.
Pulled the 545 out of a few 04-05s ,and dyno them with a r46RH, not the cheapest way to pick up 30hp....but way cheaper then rebuilding the 545 2 to 5 times before the owner finally listens and dumps the trans.
I've done two 04's and three 05's with 727 swaps, 1 of each 04 and 05 were stock(ish) the 04 had Crower cam some where in the .480-.490 lift , @.050 20X/21X, that truck made 325 with the 545 trans, made 370 after the 727 swap.
The 05 was stock except Headers ,cat back Exhaust, made 290 with the 545 and 330 with the 727.