Just buy a Gen 3 or Gen 2 and have some steel sights installed. Night sights are nice, but if you're in low light you will use your flash light and it will drown out the tritium. If you can, buy a police trade in. The round count is normally low, and police trade ins are normally solid function wise. Before people freak about buying a used gun for duty use, I was issued a used gun when I became an LEO. I haven't had any issues with my G22 Gen 3 other than some X200 induced malfunctions (another worthless tacticool mandated accessory)
As a corrections deputy your duty gun will spend more time in a locker than in your holster. No guns in the jail.
Summit has some Glock 22 trade ins for $350. HERE
If you are allowed to, buy a Glock 17. 9mm is half the cost of .40 to train with and a good +P 124 JHP will ruin some SOB perps day.