Hello Lucas,
The parts are good to use. The XXXX out information was pistons originally manufactured in 2020 that was sorted, CMM measured, and then fitted with the slipper bushing. The new 01823 date means the pistons went through the process and are found good to use. The 01823 means these pistons were confirmed good on the 18th day of 2023. You can install these pistons.
Thanks
Mit freundlichen Grüßen / Kind regards
Michael Turner
Sr Service Engineer – Series 50/60 and 2-Cycle
------------END INSERT--------------