Series 1 is the one with out the indent in the coin, meaning the sticker under the hologram is not embedded but on the back of the coin, right?
Series 1 brass 1 LTC coins have the proper indentation for the private key under the hologram. The difference between Series 1 and Series 2 brass coins are that they use slightly different holograms. The series 1 uses the same original LEALANA holograms as all of my silver Litecoin products while the Series 2 uses one that has a number overprinting as well as "1 LTC 1 LTC 1 LTC" on the upper portion. The scaling in size of the design of series 2 is a tad bit smaller. If you put the two coins types next to each other you will see what I mean.
It was the original 1/2 troy oz silver 10 LTC coins that were missing the indentation.