Speaking as a real-time software engineer I find this highly unlikely.
I recall reading that many safety-critical software systems providing multiple levels of redundancy use the talents of at least two non-intersecting groups of programmers.
The two teams are tasked with achieving the same software goals but are not allowed to cross-pollinate in terms of algorithms or code; thus trying to ensure that a programming flaw or bug is not induced into ALL parts of the system being created.
I don't know how much the software has changed since the first aircraft were sold but there was a fair amount of controversy during the development of the 777 because Boeing opted not to use parallel programming teams but loaded the same code on redundant systems.
Like I said, I haven't followed the changes in the systems over the years and it may well be that a subsequent update changed this.