<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by doobierw:
On the -10 there is no lav in the front.</font>
Bingo. That has always been my way of identifying that I am on a D9-10. I also count the FC seats, but no lav door is the real tipoff as you enter the aircraft.
I get them not infrequently MEM-SDF, as recently as last week.