I see record numbers at the bottom, top right or left and along the side. Which one is the priority?

The number on, or closest to, the No. line is the record number. You can also check your +1 reference image to see if one of the numbers belong to another document (ie, the PET number on the DEC). Entry 2 on Image 2 of this batch shows two numbers. 184463 is the record number. 751 could be anything, and it's not my job to speculate on what that means.

[MQ2J-6G2]