There may have been different specs for different markets, I also don't know whether the bike was all original-spec when you got it, but for the USA market the America was always spec'd with 700c wheels, not 27". So it shipped to dealers with tires labeled 700x28c, though I think they actually measured narrower.
Originally Posted by
Het Volk
So - this is interesting, because when spec'd with Panaracer 28MM tires for a 27" rim, the tire rubbed against the fork....which supports your statement. Likely, they were originally spec'd with 25MM tires, at 27" (while badged at 28MM), which allowed for the tire to work with those clearances on an older 27" rim.