Hi There, 

After seeing Tony's Build card, I can see that the numbers (like 100,
102, etc.) I believe, do refer to the unit codes of the sub-assemblies. 
I see that the 13-3/4" is the spindle length.  Seeing the build card explains
a lot.  Also, the "N" does refer to the UMD drive assembly (but the card
does mention something about a maple top with 8 drawers substitute
for the steel top).

Reading the Build Card has been very educational.

Good Luck!
-Blue Chips-
Webb