[Arubalisa]

I was always under the impression that 737 and 757s' were entirely different planes.
http://www.airliners.net/aviation-forums/general_aviation/read.main/3082384/

I am not usually a big fan of using them as a resource, but this is logical http://en.wikipedia.org/wiki/Boeing_757
"Variants

There are several variants of the 757. The 757-200 was the original, launched in 1979 with introduction into service in 1983. The 757-300 was launched in 1996 with introduction into service in 1999."