All Superdutys 99-08 that are singe rear wheel models use the 8x170mm bolt pattern.
Old body style(OBS) is 8x6.5
The 05-08's have larger brakes so the backspacing is different than the 99-04's.
In 05 ...engineers to upsized brake rotors by 5 percent, to 347 mm in front and 340 mm in rear.
Other improvements include larger calipers for both the F-250 and F-350. The front calipers have twin 60 mm pistons - up 11 percent from 2004 - for better braking feel. Rear calipers have twin 48 mm calipers on F-250 and twin 54 mm pistons on F-350 dual-rear-wheel models.
BACK SPACING
99-04......4"
05-07.......18"and 20"(from the factory) have 5.80" BS, and the 17" have 5.50"
00-04s came with 16s (unless it was a Harley Edition, they had 18s)...they don't clear the calipers on the 05-08s.
A 04 HD wheel would fit on a 05-08 since they were 18s, but they had less backspacing so they sit further out of the wheel wells on 05-08s.
05-08s fit on the 99-04, just rub on the leaf springs and sit further under the truck than they do on the 05-08.
Offset is the location of the wheel mounting surface in relation to the true center of the wheel......normally in mm.
Negative does move it inward.
So....
A 20x10 wheel with a 4.5" BackSpace will have approx -24 or -25mm offset.
A 20x12 wheel with a 4.5" BackSpace will have approx -51mm offset.