The lock up torque converter will not slide into place of the non-lock up torque converter and ise a versea.
With tha pan dropped, you'll find an extra tube on the valve body denoteing it a lock up.
The vin# on the side of the tranny should provide a clue I beileve.
If the trans is OE to the car, it is not a lock up.
OH, Non lock up is prefured for racing and general use by most, I have a lock up in my Duster because the engine / tranny are from a '79 year. I prefur this since it can help assist in mileage gains, however minor they are, I'll take the slightest advantage/gain in these area's.
Converters for lockup tranny's are more expensive in general due to low production/useage. MoPar sell's ecno converters. Good for general performance at a very inexpensive price for ethier style.