These are meant for a Sig P238 and P938. We do not have the exact specifications for the dovetails used on these handguns. You would need to contact Sig Sauer directly for the schematics on the slides.
This is the only set of Trijicon Sights for the Sig P238. I recommend using the Sig #8 Rear sight for your gun which is taller than the rear Trijicon Bright & Tough 3 Dot Green Night Sights for Sig Sauer P238. Or using the set at the link below.
https://www.opticsplanet.com/sig-sauer-sox10001.html
No, these sights are for the .380 models of P238 and P938.
If by "sight picture" you are referring to point of aim/point of impact, there should be no change.
Mark H.
The tritium tubes have a life span of approximately 12 years. If your lamps have gone out then you can have them replaced by Trijicon. They can be contacted here: https://www.trijicon.com/contact-us