It was some time last year. If they list the serial number (even part of it) or have a pic that shows it you can tell which one it is. Older style will have xxx-xxxxx (mine is 376-xxxxx). New design has no dash. Also, the sights on the new style are obvious whereas they are almost invisible on the older style.
I haven't followed the changes as I have abandoned the 380 cartridge altogether. That said, based on your pictures it looks like they also started putting a blue/black finish on the barrel hood vs the polished SS look. That might help to identify the guns if you cant read the SN# or see the sights.
Judging by the stainless barrel parts and the 890 serial I'm guessing the one in the 2nd pic is a special model. Mine is all black and its a few years old.
I also ran across this on Rugers site with serial number history
http://www.ruger.com/service/productHistory/PI-LCP.html