They are not the same serial number, well exactly. They have different prefix letters for their respective Federal Reserve Districts A thru L.
was new to me too. I had it for about 6 months before I noticed it. almost sold it in a star note lot I was going to list on ebay. I looked it up and noticed it was a 320k run so I put it aside instead. then while I was looking for something on a shelf it fell and when I picked it up my eyes landed on it right and I happened to notice it. that was a close one. now I keep my eyes on all my star notes
Each district starts at 00000001A with the appropriate district prefix. So, yes, there's an A00000001A and a B00000001A and so on up to L00000001A. If the series runs long enough that additional suffix letters are required, then there can also be A00000001B and B00000001N and things like that. The term "serial number" refers to the whole thing, letters included. There will typically be lots of serial numbers that have the same eight digits but different letters.
Of all the Star Notes I have, I've only ever found this kinda Fancy one... well, maybe two... I have this one and another only a few numbers away (ending in 51, so I almost found consecutives) I must have gotten them in change around twenty years ago...