Nice find. Not saying your LBS is wrong, but look on the portion of the stem that fits into the headtube and the diameter should be engraved on it near the 'miniumu insertion point' line, I just mention this since Trek amde a few bikes with odd size quill stems in teh late 1980s-ealy 1990 (I've got a 1992 8000 MTB with a 25.4 stem). It should be easy to get a 22.2mm quill stem from one of the online bike shops. You can find some more pricey ones at Velo Orange that have longer 'stems' so you can raise the handlebars higher (the Nitto stems).
One more thing . . . .we need to see pictures ! ! !
