AC
It is not unusual for higher volume users to have a customized (now proprietary) variant part built to order.
It could be anything from additional/tighter QA tests to a slightly different 'action'.
(I used to work in 'test engineering'. We used to furnish IC's that had a really tight (cherry picked) spec for the OEM customer. The 'fallout' was still a fine product and got the standard part label. Just not the
normal tolerance distribution spread
)
The bottom line is there is only one place to be assured of getting the EXACT part... That is the Mouse suppliers stockroom.
All else is either 'close' or a
fraudulently obtained design
