Modification number: (modif) 3354.  This solenoid is functionally equivalent to the un-modified version but the modifications increase it's quality.

1. Locktight on the mounting screws.  This helps in higher vibration settings.

2. Different internal lubricant that is higher quality.

3. Internal rubber (elastomer) is viton: better at high temperatures and when exposed to chemicals and oil than the standard rubber used.  

Thanks for looking!