Felix,
Not at all, your memory is perfect...it is said down here that:
Initially the AB-20 was intended to have three engines like its predecessor, but during the design phase there was a military request for a bombardier's position and a gunner's cockpit in the nose, which required the removal of the centre engine and its replacement by two extra engines wing-mounted outboard of the centre section.
https://en.wikipedia.org/wiki/SAB_AB-20
http://dev.museesafran.com/wp-conten...12_0047441.pdf
https://www.flightglobal.com/pdfarch...0-%200178.html
It was a huge monster...and weird design....
A.