Piston Identification Help

[ILENGINE]

590406 is not even one listed for the OP's engine.

From the IPL for 12H802-2677-B1

Jan 13, 1997 - Sept 3, 2007

Piston and Rings.
View attachment 62646
Jan 13, 1997 - April 16, 2009
View attachment 62647
View attachment 62648
The 791097 is superseded to 799063 Lists for $68
The 791326 is superseded to 799064 Lists for $91

This what I found on the B&S parts website

Looks like the 590406 is a complete piston/ring assembly with included connecting rod. As opposed to just the piston/ring assembly. So you are both correct.