Correct Traction bars for '69 Nova

[MonteMike79]

Hey guys, I'm new to this site and have already found a lot of great information. I have a question that I can't find an exact answer to after hours of searching. I want to know what would be the correct Lakewood bars for my '69 Nova. I have seen the square tube early bars and the rectangle tube bars, and ones with the clamps in front of and behind the axle and ones with the clamps just on the front. Which ones should I look for that would be correct. I guess I'm looking for a crash course history lesson on these bars, and which ones were produced when. I appreciate any and all help.