Hi Jimbow39,
It so happens I had mine out today and have her strung up still. I just measured it and the top limb is 7 1/2 and the bottom limb is 7 1/4. This is measured right from the junction of the limb and the end of the riser. If measured from the end of those long fades its 6 1/2 for both limbs.
My bow is also 64" and was made in 2001.
Do you know if the limbs are original to the riser? Perhaps that has something to do with with the large difference. I don't have a lot of experience with limbs failing, but it would seem to me that with modern laminated limbs it would most likely fail in a spectacular and frightening way rather than one in which tiller warns you as it gets out of balance. But either way maybe it's best to have the bowyer check it out.
Steve