I cannot speak for Greg, or others on ADR, but I can say that Van Mol certainly 'aided' riders that were willing to take the plunge into the murk of PEDs. In the lead up to the 1989 World Champs I was sent, via a soigneur, a collection of 'preparations' for the intensive training period... most of the products were innocent enough: injectable vitamins, minerals, glucose-phosphates; but there were one or two products that certainly contravened the FICP listing. These were unceremoniously dumped in a rubbish bin. Our program on ADR was split between 'the big-boys' (Lemond, Plankaert, Van Holen, Hoste, Kuum, Lammerts et al) and 'the also rans'... a great deal of this era's practices can be accessed via Joe Parkin's 'Dog in a Hat' book. Joe rode for ADR's 'second-team - HUMO, and has similar recollections to myself and a lot of the younger guys on the team. Whilst the younger guys were rarely witness to 'practices', they certainly occurred.
I for one would be devastated if it came to light that Greg was doping in 89... but such is my cynicism that it wouldn't surprise me either, knowing what I know of the team structure.