I believe that is the main difference between the 04 cylinders and the pre 04 is the cooling fins they should be interchangeable as well. I know from reading numerous threads on here that the same Axtell 1250 kits are used on both so there can't be much of a difference.
04 1200R 90+HP/10.5-1 SE pistons/.536 cams/Heads by MR T/mikuni HSR 42 w/25 pilot, 96 needle, 170 main/TC88A ignition w turbotas mod 33 map pos.4/ Supertrapp 2-1 w 23 disks/ 28T FRONT PULLEY /NRHS Hurricane A/C & adj. pushrods /progressive 440 shocks & fork springs w/10 OZ SE fork oil
i tried to see differences in the pics online but... they really look the same kind of cylinder... i asked this to a seller says about the conversion kit that are 2 different models, but when i asked wich are the differences he answered "sincerly i don't know... i never seen them in comparision"
i really hope they're more than similar