You have to get them from Compasseco or Umarex. The reasaon a JM seal wont work is because the RS2 seal is attached with a screw not a dove tail.
If you call compasseco and ask them for seals to a TF89 they will work but they might come undersized and you will have to warm them up and squeeze them in a clamp to expand them and then size the seal. Seals from umarex will be for a hammerli Titan or razor.