Yes it is reverse threaded for sure. Just went through this one not too long ago.
Is The Bolt On A Craftsman Mower Blade Reverse Threaded?
Additionally, you can determine any reverse thread fastener by virtue of "cuts" on the fastener head which are typically a double row of narrow indentions on each edge of the bolt head or nut. Don't forget to torque these fasteners per mfr or size /grade standard.