I would not just assume that you have a 120/240 3 phase 4 wire service, particularly if there are 3 pots on the pole. In most areas that provide 3 phase high leg service it will be 2 pots open delta. 3 pots in most areas would likely indicate a 208Y service.
And as others said, in many cases you can operate equipment designed for 240 on a 208 system but not vice versa. With resistance heating equipment in particular, this could lead to serious problems.
Quite a bit of full delta with high leg around here. Retail, restaurants, offices... more likely to be wye, especially if newer building or newer remodeled.
Farms, small industrial, etc. with motor loads being majority of load, 240 delta is preferred. Little less amps for same load, can easily run single phase 240 volt equipment with no issues or at reduced power levels.
In more recent years farming operations have changed though, everything is bigger than it used to be. Big grain storage operation 30 years ago might have been three phase, very few were 480 volt three phase. Maybe only 50 - 100 HP of loads. Past few years most of those I have done were 480 three phase though, with sites that have 100-200 HP worth of motors or more.