jackblack1, your post raises a broader question of how beginners approach the mountain of information on how to identify a stamp - especially when there is a rare one that looks just like it.
The Scott US Specialized catalog has a very good identifier section for regular issues in the front, but does not provide guidance on a separation scheme to most efficiently determine which stamp # you have. For some series I might start by checking the perforations, in another series the watermark, the engraving details, or the paper, etc. So it has to come through the experience of slogging through piles of stamps.
For this series, For the sheet stamps I always start by checking the perforations on the long side. I will get piles for perf 10, 11, and 10.5. For all denominations except the 1 and 2 cent, I am done since there is only one possibility. The 1 and 2s that perfed 10.5 on the sides are also done except for a quick check for 634A. The rest will require perf checking on the top/bottom and only then is there a need to measure a few much smaller piles for flat/rotary, which is too detailed to get into here. Others may have a different variant of a scheme.
