Yes it is, not something off the shelf, but an enclosure that will fit the gateway should be available. You should contact a supplier of IP67 rated enclosures. You could start by looking at outdoor enclosures used for WiFi access points. (Google is your friend)
I build gateways into IP65 enclosures for industrial outdoor use. Usually IP65 rating. IP67 is very serious! It means you must support being submerged 1m under water for 30 minutes with no water entry. Is this really what you need? LoRa will not work under water! Please see attached picture. Steel enclosure is used to get good RF shielding. Cable glands, etc. also need to be IP6x rated. Grounding is also essential.