getting Current script version using Google Apps script

If you mean "Can we programmatically retrieve the script version number?", the answer is no. There is an outstanding request for this, in Issue 1369, so visit the issue tracker and star it to indicate your own interest.

Perhaps you mean "Can we programmatically retrieve the most recent source code?"

You can Import and Export Stand-alone script files through the Drive SDK. In Apps Script, this can be accomplished using UrlFetch Services.

There is no way at this time to retrieve the source of container-bound scripts, except through the Script Editor. (See Limitations.)