I've got a Mk2 with the JCosta. It was fitted by a Tmax-Group member while I was in Germany, 2 + years ago and like you,, I don't know what the weights were.
Clive changed the weights for me, last summer. The new ones are 16.5gr and they, nor the old ones had any marks on them as I remember.
There doesn't seem a great deal of difference in performance from the old weights. Would you get 2 packs the same in a kit?
I do know, there seems to have always been a lot of vibration. Not noticeable in normal riding but when using a bit more revs,, like last Sunday, trying to keep up with Clive,
it looked like a case of vibration white finger when I got home.