There were some US wrist alarms with sterile outer dials, but this is because the LeCoultre brand had been moved to the inner dial.
Think DSA US version with 'sterile' outer dial, and other US-typical versions such as this one:
This definitively conforts me in thinking this WT is franken / fake (and BTW, there are very few references which are documented as existing in WT, and this square one is not among them)
And if a further proof is needed, that very dial we see on the auctioned 'WT' memo was sold some time ago by a german seller (and it had the matching slate grey inner dial which it has since lost to a non-matching black WT)
I guess we now know where it ended...
Now, regarding sterile dials, I have a small memoclock which has a sterile dial, only JaegerLeCoultre printed / engraved on the back...
(and obviously, there in this one there is no outer dial so no place to put the logo or it would be rotating)
On this one the dial in its totality is the alarm dial, interesting...