The Firenze was a sweet bike, and exceptionally priced at the time - right around $1000 - we sold half a dozen or so. Although originally advertised with red, blue or gloss black Galli gruppos, we also got one with the transparent black/midnight blue color, and one with gold. The gold was not as rich as the color Modolo used on some Professionals, but it was nice, and very rare - this was the only gold gruppo I ever saw, and we built a lot of bikes with Galli.
None of ours were special requests - we simply called the distributor (Bicycle Parts Pacific, IIRC) and asked what was available in the size we needed. It's possible that they had bare frames and gruppos there. All the frames were pearl white - no option there, and the paint quality ranged from adequate Italian to stunning. The last one I remember was specced with the semi-aero hard anodized clincher rims - (Aero Pros, maybe?), rather than color matched Top Crit tubulars. The parts were occasionally a random mix of Criterium and KL-Aero: always KL-Aero calipers (very similar to Universal Squadras) with standard levers, rather than the plastic bodied KL brake levers. We saw both KL (Stronglight 107) and Criterium (Stronglight 106) cranksets. Shift levers were both the Simplex Retrofriction sourced and the older ones that looked like milled out Campagnolo - none we received were color matched. 3TTT bar and stem, and the seatpost was usually 3TTT marked, rather than Galli branded. Don't remember the pedals - we were pretty heavy into Look at that point - but they were probably the usual Galli-stickered Maillard 700s, as were the hubs. The more I think about it, the more I think maybe BPP assembled these in house - the consistency in components was a little too random.
So, anyway, the nice thing is that you've got some leeway in the exact spec, so long as you get the brakes right! I love the Galli components from that era, and would be happy to stumble across a decent gruppo myself.
Good luck with your project, and Happy New Year!
Derek Vandeberg
Bigfork, Montana