To the best of my limited knowledge of these, the early ones (I presume one like yours) were made with one extractor. Later they were made with both a left and right extractor,
The repro's AFAIK are copys of the later design and have the duel extractors,
I do not know it the early style used the same single side extractor as the later double extractor design.

All that aside,,the go to guy in a CowBoy Shooting Sports for '87 rebuilding (repro's and orig) is/was Tom Wildenauer
The last contact info I have for him was:
E-mail: lassiter45@aol.com
He goes by the name Lassiter on the SASS forums

His shop name I have listed as:
'Tom's Single Action Shop'
New Lebanon.OH 45345
937-687-1039

This info is from my notes of a while ago so no telling if it's still valid.
But an email or phone call will tell you quick enough and if he's still in the biz he can tell you straight away about your Mod1887.


You come up with the damnedest stuff..!