You just verify the IS-IS metric must be between 1 and 63. There is no default-metric option in IS-IS-you should define a metric for each protocol. If no metric is specified for the routes being redistributed into IS-IS, a metric value of 0 is used by default.
Administrative distance you saw how redistribution can potentially cause problems such as below optimal routing, routing loops, or slow convergence. Avoiding these types of problems is really quite simple-never announce the information originally received from routing process X back into routing process X.