Is the "confirmed allocation" string in "A Scandal in Belgravia" a real airline practice? (This is a repost of this question on Movies SE. I hope to get better answers here.)

Irene Adler shows the following text to Sherlock:

007 Confirmed allocation
4C12C45F13E13G60A60B61F34G34J60D12H33K34K


He immediately guesses that "these are seat allocations on a passenger jet", claims it must be a Boeing 747 and then recalls a specific flight which takes off at 6:30 PM the next day. Note that only 14 seats are listed. A Boeing 747 can carry about four hundred passengers. The flight takes off tomorrow evening.

Do airlines really document or communicate seating allocations in this way? Shouldn't there be more seats "confirmed" (whatever that means)?
No

Based on my research for string confirmed allocation, there were no references found related to airlines or their practice.

However, the background scenario about the conversation Sherlock was having, something like the following had happened (references: this and this and this and this and this):

(my paraphrasing, not actually a quote)


  Sherlock knows that 007 is a flight of Bond Air which is leaving for
  Baltimore tomorrow at 6:30pm. He is aware of a terrorist plot of
  having dead bodies on an airplane (14 seats allocations) so that no one actually dies. The
  first 0 in flight number indicates that zero causalities will happen.


P.S.: This question is not about aviation but movies.