Yup that is why I'm going with the 2 speaker replacement for up there. Hopefully no hole to cut.
The only holes for the 2 speaker setup will be the 4 mounting screw holes, plus a hole for the speaker wires. IIRC, I went 3/4" for the hoe for the wires as it made it easier to run them. I also added a grommet in the hole to prevent chafing of the insulation.
I do find them to be a bit "tinny" sounding, ended up adding a pair of 6x9s in the cab corners to balance it out. Ammo cans make perfect cab corner speaker boxes for TF trucks. Paint them up to match the heater, they look like they belong there.