Hull change?
 

What years were the 37 hulls modified?

1999 the the DDC step was introduced to the 37 Offshore Straight Bottom hull.

2003 the top deck was raised just a bit to allow for more headroom.

Though the years, the step has been between 5 inches tall and 3.75 inches depending on the power package and purpose of the boat. The clear majority of them are 4" tall though.

That's the extent of any changes.