Fleetwood/Coleman only used one size of track. I'm not sure what JC Whitney is feeding you for info. Coleman makes their own awnings- but I would measure the actual slot that is on the track. This is the critical dimension.
If you have the one piece ABS roof- forget about replacing the track- the original is glued on and rarely comes off.
What is wrong with your awning? The devil you know is way better than the devil you don't know with an aftermarket awning.
I've never heard about different size awning tracks. I did that gig for 12 years- so I'm not blowing smoke.