Kris with a repaired ganya?

[Green]

I bought this kris from epray recently and the following pics are from the seller as I've not yet recieve it.The seller dated this kris as 1930 although some people I showed the pics to said it could have been somewhat later (early post WWII?) is 1930 reasonable?

I have several Qs that I hope some of you can give answers to . (Many thanks in advance).

1) The fitting of the gonjo to the blade looked very much as if it was repaired to me. See yellow arrows in one of the pic. The lines did not match.

This look to me as though the part of the ganya (circled red) was broken and reattached? Is this assumption correct?

2) I like the look of the markings on the blade. Is this typical markings/decorations specific to a particular tribe?

3) I was told that this type of marking is a later style and only occur in blades from early 20th century onwards. Is this true? meaning that we can date a blade based on absence/presence of this type of decoration?

4) What tribe produce this syle of blade?... check on old posts in this forum mentioned Sulu or Miguindanao. Which is it? or both tribes?