Hi ,
what I wrote about the LE8T isn't possible as Grumpy stated.
I have only two of 164 with SN and the (unconfirmed) date of 1985 with the numbers 37447 and 37457.....but this can also be a result of the owners (wrong) declaration of the age.
C54 in the registry go from 67110 to 70277 without any date and PR8 from 10011 to 58019 also without date.
HP