message_id uniqueness?

[Matthew Hixson]

As I understand things the SMSC is in charge of creating message_ids 
for each SMS.  Should there ever be a case where two consecutive SMS 
messages are assigned the same message_id?  I ask because this is what 
I see from a recent test while sending a ringtone that was chopped into 
two SMS messages.  The message_ids in bearerbox.log were identical.
  Is this normal?
  Thanks,
   -M@