Gerald Belrichard said
I was wondering if there is a way to verify if a model 1890 with a threaded barrel and cap is original from the factory or if it was done afterwards.

I will try to post some pics.

Thanks in advance for any info and response.  jb  

Pictures will help, but the milled style of the threads will tell the story.  Specifically, the threads will be milled interrupted if factory original (allowing for a simple 1/4 turn to install or remove the silencer) and will be blued.  If the threads are cut 360-degrees, or in the white, it is aftermarket work.

Bert

Gerald Belrichard said
Thank you !  So by interrupted do you mean like on the Model 12 barrel ?  

Yes, or like a Model 1886, 1892, 1894, or 1897 Take Down barrel.