How many crank position sensors on 1991 Cadillac Deville and Part#(s)?

1991 Cadillac Deville:

1. Is there just one or are there two crank position sensors on this vehicle? If two, are they the same part number?

2. What is the crank position sensor (CPK) Part number (213- )?

2. Where is (each?) CPK located on the engine?

3. Any special info for replacing?