With the exception of 1878 (which has no normal die), VAM 1 means normal dies with nothing notably out of place -- no doubling, no date or mint mark position deviations, no die damage, nothing. This can be consistently one of the most difficult attributions to call, as you have to come to the conclusion that none of the diagnostics present for all other VAMs of that date are present on the coin being attributed and there are no features that warrant a new listing. It's also quite an anticlimactic attribution, since much time is spent determining there's nothing special there.
Currently, the only date without a VAM 1 is 1880-CC. No coin with two normal dies is known to exist, as they're all overdates with different degrees of repunching apparent. For other dates, as detailed die studies are being done it is possible that VAM 1 could become unknown, with all die pairs exhibiting some feature significant enough to differentiate it from normal.
Welcome aboard! Your question is a little tough to answer, but I'll give it a shot. VAM-1 would basically be the first die class recorded for each date/mm by Leroy Van Allen and George Mallis. MOST of the time (but not always) this would be the absolute vanilla die pairing. Like a normal date placement with a centered, upright MM and these VAMs would show no other listable characteristics. Many of these VAMs could/would of been made by numerous die pairs. Every Morgan and Peace dollar IS a VAM, but they are certainly NOT all VAM-1's.
Please click this link for the full VAMworld.com definitions page.