All of the above listed 2nd stages are all Mares. Just different models. You should get 1 kit for the 1st stage and 1 kit for the Mares 2nd stage that’s made for the model of the 2nd stage. There is no reason why the seat didn’t come with the kit. There are 9 different models of 2nd stages that have been sold with the MR2 and 3 different service kits for those 2nd stages. Your Mares poppet seat part # most likely is 46200204 unless if its an octopus. I have one seat here so give me an address and I’ll send it to You. Scuba80@hotmail.com