I'm thinking of selling my STX and am hoping for some guidance from the forum.
I purchased it new and have never fired it. It has a 2014 mfg. date. I think I recall reading that the STX is no longer being produced by Sig. Can anyone tell me if that is the fact?
I have other sig pistols that I shoot as well as a S&W 1911 so I never saw the need to shoot the STX.
Do you think it's worth keeping as a 'collector' item?

I have no idea on any of that. but you can easily see the sig catalog on what's current https://www.sigsauer.com/firearms/pistols/1911.html
And I can say without hesitation the odds an STX is a collectors item border on near zero.

I don't think there will be any "collector" value. Sig introduces and discontinues a lot of models. Values are probably as high right now as they have ever been and higher than most of the last few years.