The F-37 consisted of 3 parts - 1) detuning the engine power curve and 2) changing the transmission shift points and 3) checking for torque converter problems and replacing if needed (the only for sure replacement was the early TCs with a plastic part that all died young so to speak). I could be wrong but IIRC all 05s and some 06s came out before the F-37 but some late 06s had the F-37 steps 1 and 2 (3 was not needed as TC replacement was only applicable if driving damage occured) done during manufacture

You would have to have access to a factory or equivalent code reader to determine which ECU coding you have relative to engine detuning. Checking the VIN may or may not help as I know of several vehicles, mine included, that positively had the F-37 "done" but equally positively did not have the transmission shift points changed. The odometer and speedometer can be off +-5% either way and independent of each other. If you have access to a GPS find a flat stretch of road and on a warm engine run (moderately not flat out) up to just shy of 62 mph. If you feel and see, on the tach, a noticeable drop in engine rpm shortly before 62mph AND at just a hair shy of 62 mph the rpm is about 1,800 your transmission has not been F-37d. However, if at 62 mph the rpm is well above 1,800 and you keep accelerating and then feel that shift the transmission has had the F-37 performed.

GDE can take care of that but you need to send in your TCM to be programmed.

Speedo points as opposed to rpm points I don't know. My speedo is essentially dead on compared to GPS and stoutdog's was pretty close. I do know that 62mph on my CRD without the tranny part of the F-37 was 1800rpm and on stoutdog's with F-37 the rpm at that speed was much higher unless he ran the speed up enough to make the "final" shift and then dropped back to 62mph. We both now have GDE's tranny tune so it no longer matters