Do the RJ45 Modbus RS232 ports of the TSXETG100 and the 174CEV30020 have the same pinout?

No — the two ports use different pin assignments, shown above. If you're building or buying a cable between these two devices, you can't treat them as a straight pass-through; the signal on a given pin number on one side generally doesn't match the same pin number on the other.
The pin assignments of the ports are as follows: