Congratulations on getting a good deal on your rifle. I cant weigh in on the recent or older production question but others here surly will provide you the answer on that.
I can tell you my experience with my LMT MWS 20" .308 and a SiCo Omega is it not good. SiCo Omega is a high back pressure can and will beat up your rifle and your brass. After 40 - 50 rounds my rifle gets so much fouling in the system I start to have reliability problems. There is a good amount of information in this thread on the topic.
You can fiddle with the gas tube, buffer size, spring ect.. to get it to a reliable or you buy a low back pressure can like a Huxwrk or Surefire. That is the route I am going. Of course cost $$$ and a bunch of time. Read this thread for more.
HTH
I can tell you my experience with my LMT MWS 20" .308 and a SiCo Omega is it not good. SiCo Omega is a high back pressure can and will beat up your rifle and your brass. After 40 - 50 rounds my rifle gets so much fouling in the system I start to have reliability problems. There is a good amount of information in this thread on the topic.
You can fiddle with the gas tube, buffer size, spring ect.. to get it to a reliable or you buy a low back pressure can like a Huxwrk or Surefire. That is the route I am going. Of course cost $$$ and a bunch of time. Read this thread for more.
HTH