I would say yes. An LSAT prep course can push you up 3-10 points. Powerscore is pretty good. You will probably bump yourself up about 5 points just by reading a prep book like the powerscore or Manhattan LSAT. 15 points is a lot, but I've seen people jump 20 and even 30.
And kudos, you are a rarity.
Sorry MisDirected, but statements like this are just bad. You need to clarify it and qualify it. A jump from 150 to 160 is not relatable at all to a jump from 165-175. Saying a prep course can push you up 3-10 points is wrong for many people.
If this person got a 165 on the first practice test (I got a 171, and ended up getting a 160 actual) then he already has speed, reasonable awareness, focus, and he gets the point of the exercise. A 165 actual score is in the 92nd percentile. A 175 is in the 99.4 percentile. A 175 is absolutely crushing the test.
Prep courses don't increase your intelligence, and they don't give you any real secrets. THey help you manage your time, they help you get used to the wording, and they help remind you to practice. Sometimes prep courses can even help you identify patterns.
Now, if the OP got a 165 because he ran out of time on three sections and didn't answer four or five questions, then yeah, practice and a prep course might go a long way.
I have one buddy who is now a great attorney. He had a 3.7 GPA and he consistently acheived practice scores close to 160. He took an intensive practice course, quit his job for a few months, and studied like crazy. He ended up with a 154.
Living Legend's post is spot on.
Still, Scores over 168 on the real thing are so very rare. Only 4 out of 100 acheive those marks... so I think the reasonable answer to the OP's question is, don't count on it.