This is an immaculate Trek TX-900 with original Campagnolo, Brooks, Cinelli, Suntour, and Rigida components
Lugged Columbus steel frame with gold painted lugged holes.

What is not original (other than probably cables, tires, handlebar tape etc.)
--Replaced original 38 cm Cinelli handlebar with a 44cm Cinelli
--The cable bands on the top tube are Specialized

5 speed Campagnolo Nuovo Record drivetrain.
Campagnolo 52-42 crankset (170mm)
Campagnolo (didn't verify) 13-29 (if my counting is correct) cassette
Campagnolo down tube shifters
Campagnolo Christophe pedals
Brooks Professional Select saddle
Rigida wheelset
Cinelli stem and handlebar
Suntour Superbe levers and brakes.
Vintage Cateye computer

This TX-900 has the original fastback seat stay, which was discontinued the next year. It was labor-intensive to manufacture.

It is difficult to determine if the frame is 61cm or 62cm. 24" is about 61cm, however, on the left side of the head tube is the number "62"
The S/N appears to be "J4C S07" (or "807), which would be TX-900, 24", March 1978. But it is difficult to read, and I talked to Trek and they had a difficult time deciphering the S/N.

On the right side of the top tube and head tube are the numbers "73" or "78" (could this be for 1978?).

SHIPPING NOTE: Shipping costs vary. If shipping cost (plus fees) is less, the difference (with numerical rounding) will be refunded.