Here's a speedo and tacho assembly in very good condition, taken off a Yamaha SR500. The clocks show minimal signs of rust. The speedo has a few mm long scratches on a corner and 1 very small dent. The cables are all intact and working. The speedo shows 14.429km.
The clocks can be mounted on all SR400 and SR500, but depending on the model, changing the cable sockets and some adaptations may be necessary.