This was listed recently on a well known on-line auction site…
The vendor lists the frame as being from 1972, but given the Colnago lettering inside the seat stay hollow, I’d say more likely late ’70’s-early ’80’s, and the gruppo is Campagnolo Victory, so later than the frame..
the frame was ahead of its time, as it has an internal cable guide on the top tube, which wasn’t implemented on the ”off the peg” Colnago frames until the early ’90’s
the brake calipers are also at the rear of the front forks and and rear stays, for aerodynamic benefits
also of interest are the forks, no caliper bolt hole at the front, Colnago stamped near the crown, and an aero profile..
There is only one shifter on the down tube, with one outer chain ring and also integrated wiring,via down tube and exiting the bottom bracket shell underneath the chain stay…
There are crimps on the down tube,top tube, seat tube and on the inside of the stays, very rare for a Colnago Mexico..
the stem and bars are unusual as well, the stem would also compliment the Colnago Oval CX, and the quill part is smaller than normal stems, and the bars are stamped in black 3TTT..
for something this unique, I don’t think the price is extreme, and I have actually bought parts from the vendor in the past, and would recommend him.