Most of the Ewok Items I have that are vintage sink, I do have a Chief Chirpa with his staff The staff does float check photo 6 marked(Vintage ROTJ all float) . I also have confirmed REPO items and they sink as well here are some photos I took of my items. I do know that the plastic used throughout the whole vintage run has change from year to year the plastic used for the ROTJ items had less Petrochemical the 1977 star wars ones that is why they tend to sink more plastics today have more synthetic compounds to them which I would assume makes them heavier. I am no scientist but that would make sense to me
. I hope this helps though. I will also post this in the ID ares as well.
These are confirmed and drilled repo's
Repo cape on left Original on the right note hard to see in the photo but the texture and colour are different the vintage one is more of a pink and softer due to age and material used.
Weapons this set is Vintage Ewok with a guard ax all sink
Vintage ROTJ all float
Repo ROTJ all sink