Slide Stop, Safety Lock, Triggers, and Mainspring Housing

Magazine Release Catch Locks: The original Type 1 magazine release catch locks were very hard to remove so at approximately SN 3100 it was deemed necessary to add a grove so it could be rotated easier, since there was a large number of catch locks already manufactured a slot was added to the existing inventory and this is referred to as a type 2. At about SN 6000 the new catch locks made it to the assembly line and started to appear on the pistols, these are referred to as Type 3 and were used to the end of production.

Type 1 - From about SN 1-3189	Type 2 - About SN 3190 to 6500	Type 3 - About SN 6000 to present
Note: Both the early magazine catch body and the early magazine catch lock needed to be slotted in order for the Transition magazine catch to turn as does the type three magazine catch. The first type magazine catch body had no slot in it and it cannot be removed by turning the magazine catch lock, but the whole body must be pushed out and turned as a whole.

Sear Spring: The early sear springs were designed with out the lip on the long leaf, if assembled incorrectly it was possible for the hammer to *not* get locked back during the cycling of the slide causing a premature firing. The lip was added to the long leaf to make sure it would not be placed under the sear during reassembly which prevents the premature firing scenario.
		(Click on images for larger versions)
Early Sear Spring: From SN 1 to 1005	Revised Sear Spring: From SN 1005 to end of production