I am at this step and wanting to confirm if I have bad cables before I start modifying them.
Here is what I have.
And here is what is in the build guide.
https://d17kynu4zpq5hy.cloudfront.net/igi/makertech-3d/MskBDrdaMRmKAMRd.medium
Note that the red side is correct on the LCD panel, but backwards on the control board. Just wanting to confirm this means I have bad cables and need to modify one end to fit backwards.
These are not correct. You will have to modify one end to fit backwards. I had mine like you have yours now and the lcd did not light up, I modified both cables and it works now.
Double check that EXP1 on the board goes to EXP1 on the LCD board and the same with EXP2. I had them swapped and was having major WTF's for a while. In the end I had to cut the tab on EXP1 and flip it backwards. I did this on the LCD screen side, but I don't think that makes a difference.