Back in 1992 BMW manufactured the E 36 but the convertible E 30 was produced until that same year.
My understanding is that the E 39 style will change on 2003 and probably it will also be the last year for the M 5. One thing I can think of is that the M 5 will not be manufactured with the new body style until at least 3 years from the beginning of production of the new body style.
Take care