I bought the RGB backlight controller from BennVenn to use with a RGBx3 from Kitsch-Bent. I need to solder to 62-66 and 69 on the CPU, but when I cracked open the DMG I wanted to use, it's a CPU-07 with the black goop of doom on the chips.
Can I follow the leads and try soldering somewhere besides the CPU legs, or should I bag it and use the CPU-04 I have here even though it's in rougher condition?

yeah, following the leads will work just fine. However, if you prefer to use the 04, you can just swap taht board into the better shell.
I suggest modifying the newer CPU revision though