I think it would be vastly easier to do the required work in Lightroom compared to Photoshop, not harder, even if you presently know nothing about this program.
I realize that you probably don't have a copy of LR available to work with, but here's what you would do:
1. Put all the pix that need left and right cropping into one folder.
2. Let LR import all these pix.
3. Using one of the images that needs a left crop, switch to the develop mode and use the crop tool to select just the left hand area you want.
4. In the lower left corner, click on the "copy settings" button. Select "crop" as the only attribute to be copied.
5. In the film strip at the bottom of the screen, control-click on each of the images that needs to be "Left hand cropped". This will eventually select all of them.
6. In the lower LH corner, click on the "paste settings" button.
7. You will see all of the images you selected for LH cropping become cropped.
8. Repeat steps 3 thru 7 for the images that need a right hand crop.
9. Done.
HTH,
Tom M
