All you need to know to rebuild your own carbs cab be found in this step by step topic (tutorial)
1979 Carb rebuild Pt1
written by Scotch a few years ago. The only parts needed to do the rebuild is 3 o-rings preferably Viton to fit the float valve seats and 3 carb bowl gaskets or 1/16" gasket material and make your own. Attention to detail and follow the info and you'll be fine. Save the $650 and DIY.
These carbs sat outside on the bike for ten years and throttle shaft frozen Did partially disassemble to soak got shafts loose but would feel more comfortable with a good disassembly and sonic cleaning.