I'm going into second year and taking a poli sci course (POL SCI 2XX3) as an elective. I was just wondering it helps to take the first year poli sci course (1G06) before any of the second year courses?

2XX3, Third World Politics.

this course barely needs any prior knowledge of politics, because the course is mostly based on international countries and their issues and democracies and govts.
1G06, for the most part, was just a basic intro to politics.
you're not gonna be entirely lost, so long as you go to class and do readings.

is the prof still Dion?

Yeah, 1G06 isn't necessary. 1G06 covers Canadian topics. 2XX3 namely covers developing countries.