As an installer of spray in bedliners, I’m in the camp of bedline everything lol. If you use a quality product it can add some strength but keep in mind if you have really **** hinges it could cause future issues. I’ve sprayed bedliner on service bodies and not had any issues, that’s the closest thing I’ve sprayed to a cabinet, which really isn’t the best example. I’ve had a few customers ask about doing toolboxes but haven’t had a bite yet, been on the lookout for a cheap one to do myself just to use as an example for my products and maybe later donate or raffle it off.
Back on track, the cabinets are free, bedliner is cheap, it doesn’t take all that much talent to shoot, just make sure you prep properly and I believe you will be golden.