I did notice the Gerber thing. Talk about product placement.
Yeah, whenever Carl found that Gerber Apocalypse Kit (the roll of knives, hatchets, and machetes that they use throughout the series), they made sure to show a shot completely of the kit and focused on the Gerber logo. Nice job, Gerber, nice job.
It's actually relatively easy to make exploding arrows, but actual effectiveness in a zombie apocalypse would just be to cause a zombie head to erupt in a gory mess, and you would loose a precious arrow in the process.