Hi YS and welcome to the forum.
It's a bit difficult to full assess you keris from these photos. Firstly photos are not the best way to assess any keris and in hand a different opinion might be formed. But you have not provided a good over all photos shot from directly above so it is possible to make some mistakes regarding dhapur. But what you were told might well be correct.
As far as tangguh is concerned, the first thing to know is that it is an estimated that you keris fits into a specific style that was known to be in fashion in a particular time period, but tangguh should never be taken as an indication of actual age. Old styles are sometimes copied at later dates to to place a blade on a timeline based upon a determined tangguh can be problematic. Unfortunately many of the indicators for judging tangguh cannot be drawn from a photograph alone and the blade really needs to be held and examined in person for a better assessment. My own thoughts here is that this blade is not nearly as old as you have been lead to believe.
This seems like a nice blade and the pamor seems fairly well executed. If it were mine the one thing i would do is to swap out that old mendak that is missing its stones with a nice quality new one. This blade deserves that.
