Audio accessories decide whether coverage is usable. A radio heard perfectly on a bench is not heard at all over a running plant, and the resulting complaint is normally reported as poor coverage rather than as the wrong accessory.

PTT button: Yes. An emergency control that cannot be operated through the gloves worn on site is not an emergency control, which is worth testing with the actual gloves before ordering a fleet.

Ingress protection is IP54. Accessory connectors are where dust and moisture do their damage first; a cover that is actually used extends the life of the accessory more than the rating does.