The version is an older build of the game. Since split RAR archives are usually created by specific repackers or file-sharing sites, you must go back to the exact website or forum where you found "part01" to find the matching "part02."
If you have at least as many .rev files as you have missing parts, double-click any .rev file, and will attempt to rebuild the missing .part02.rar . 2. Identify the Version Source
Studio Wildcard - ARK: Survival Evolved is Free To Own! - Steam
Using mismatched parts will result in a "Checksum error" during extraction. 3. Verify File Integrity