No, the most boring by far concerns the 1937 penny reverse. There's two MICRO-MICRO varieties, which have something to do with whether the exergue line crosses through a tooth or not. Both are equally common, and I've never even looked to see which mine is, or the proof, as I JUST DON'T CARE I not heard of the exergue example. The pointing of the P in PENNY is the usual way, P to tooth and P to gap. There's two obverse as well. Yeah both are the differences between the 1937's... P of PENNY to tooth/to gap and sea level crosses through a tooth/above a tooth. Plus the 2 minute obverse differences, I think it's something to do with the I or the P in IMP but can't remember exactly! Definitely a MICRO-MICRO variety as Peck says