...
If the Jira versions are close they don't differ in any major features and so it is absolutely safe to use CMJ to create and deploy 100% valid and full snapshots. Also, you don't need to use the same version of CMJ, but it is recommended to use close versions of the CMJ if the same is versions are not possible, so you could get the same set of features and object support.
Example: Jira source instance is on v7.8.0 and the target is on 7.9.0. CMJ is absolutely safe to create and deploy valid and full snapshots.
Snapshot compatibility between Jira versions
...