I'm just starting a build of the same frameset - originally grey with black fork and stays, with a 1" headset. However mine has had the U-brake studs moved to the seat stays, and a cable stop bridge welded on too. To help the rear derailleur cable avoid the tyre it has had a cable guide welded underneath the stay. It's the only one I've seen with a seat stay mounted u-brake. Serial number is a very early Y025. Presumably after the modifications were made the fork and stays were painted pink to match the logos. Years on the pink looks pretty scruffy so they are off to the powder coaters tomorrow.
What do the original u-brake studs look like? Mine are quite elegant and round, unlike the boxy ones for later cantilevers. Also how was the rear derailleur cable routed - did it go through the u-brake stud? And is your serial number also a Y0-- ?
I've owned one of these frames for 15 years and it has lived in a mates shed 18,000km away all that time. Was stoked to be able to find another. Unfortunately all my 1 1/4" gear I collected doesn't fit it. Lastly - mine came with a steel Ritchey quill stem - nice looking but a colossal 170mm long!
Watching yours with interest. Cheers, Gareth