The only thing that is consistent about Chicony 51*1 keyboards is they are not rubber domes. They can have any kind of MX, Alps, Monterrey, SMK, Futaba, Mistsumi... clones of any of the previous. Keycaps can be lasered, pad printed or sometimes doubleshot. There is no way of knowing what you might get unless you can get seller to verify first. For some inexplicable reason they seemed to have simply used whatever was available to them at the time and couldn't be bothered to change the model number.
Personally I would retrobright up the doubleshots and put them MX one. It has some nice vintage blacks on there.