Coolant temp sensor question

So I bought an aftermarket Coolant temp gauge and it came with the new sensor for my RENIX style XJ (it has the dummy cluster) ... After it sitting for 6 months I seemed to have lost the sensor.
Can I use the stock sensor off an XJ that has the good style cluster?

Only if the aftermarket gauge reads the same Ohm range as the OE sender. You could temp wire it up and put the sender in some ice water.