First generation of KDX200 was: A (83), B1 (84) and B2 (85). It was loosely based on the KX125s of 1982/83
The C1 in 1986 is a significantly updated bike - exhaust power valve, 43mm forks with front disc, etc. It is loosely based on the 1984/85 KX125s.
So while most Vinduro organisers happily turn a blind eye to trail and enduro bikes that may not meet the 1985 cut-off but don't have USD forks or a rear disc, the 86~88 KDXes are not carry-over bikes.
The 86 IT200 is basically the exact same bike as the 84 & 85 models. So while the 86's front disc stops it being a strict carry-over model, it is much closer than the 86 KDX.