I'm still dating the bike as a 1991 edition.
Mainly due to the head tube mounted cable stops.
As for the drop out, I now remember that they did use 'none hole' ritchey drop-outs on 1991 models at some point. <cough, 'cos mine does and I think I've someone's Blizzard like that as well, cough>.
Still all frames are mentioned to use 27.0 in 1991, not until 1993 models did they move some up to 27.2 and drop some down to 26.8.
(from catalogues I linked too)
As for Seat post size, even if it a 1991 blending in to 1992, there is a strong trend of post diameter.
1991
Titanium 29.2 (3Al/2.5V Ti)
Altitude 27.0 (Ritchey Logic Prestige Custom Blend)
Summit 27.0 (Tange Prestige Concept)
Blizzard 27.0 (Tange Prestige Concept)
Équipe 27.0 (Tange Prestige, Quad Butted, Double Butted, Concept Blend)
Hammer 27.0 (Ritchey Logic Cro-Mo)
Fusion 27.0 (Ishiwata Cro-Mo Triple Butted)
Nimbus 27.0 (Easton #7005)
Expérience 30.4 (Aluminum #7000)
Cirrus 30.4 (Aluminum #7000)
Stratos 27.0 (Aluminum #7000)
Thunderbolt, custom 27.0 (Tange Prestige std,o/s or concept)
Tantalus, custom ??.? (Tange Ritchey Logic Super Butted)
1992
Titanium 27.0 (3Al/2.5V Ti) 27.0
Altitude 27.0 (Tange Ultimate Prestige Superlight Blend)
Vertex 27.0 (Tange Prestige Concept)
Équipe 27.0 (Tange Prestige Ultimate Super Light, Concept)
Hammer 27.0 (Ritchey Logic Cro-Mo)
Blizzard 27.0 (Tange Prestige, Concept)
Fusion 27.0 (Ishiwata Cro-Mo Triple Butted)
Metro 27.0 (Columbus Cromor Cro-Moly)
Cirrus 30.4 (Aluminum #7000)
Expérience 30.4 (Aluminum #7000)
Stratos 27.0 (Aluminum #7000)
Tantalus/Thunderbolt ??.? (various choice of steels)