Security 6 trigger--DAO??

[Mobuck]

I recently bought a complete trigger guard assembly on e##y.
When I installed it yesterday, double action worked fine but cocking the hammer manually resulted in the trigger slipping forward and the hammer hanging up halfway back. Some fiddling would achieve full cock and single action operation but not something one would want to do with a loaded gun.
I disassembled and compared the old vs.replacement and the "tail" of the trigger at the sear is shorter on the replacement.
Is this a factory DAO part or a shop modified condition?

 

[contender]

Sounds like SOME kind of modification.

 

[Mobuck]

The seller made the deal right. He sent pics of the other triggers he had for sale and all showed the modification like the one I received. He pulled his auctions until he can verify the safety of his parts.
Might be something forum members should be on the lookout for.