I think it could be done, but it would take some work & money to get to where you can make it ‘definite’.
For example, say I send you a few grams of metal from a blade I just made, 50% meteorite, 50% home-smelted steel. You send that to a lab and have trace element analysis done, you have one data point. It would be a good data point, ‘cause I can tell you which meteorite I used, and you could compare it to the unforged meteorite, there are usually reams of trace element data available on meteorites - now you got two points, which show how the meteorite material is diluted out.
But wait, the blade I did is non-homogenous (as are most keris), you really ought to analyze it more than once, or at least make sure your lab is taking that into account.
Now you check a keris (Datum three? Four?), if it’s old, they weren’t using meteorites from AZ or Argentina, so you have a different element pattern, perhaps – you could study up on element fractionation in the cores of asteroids to figure out which elements are significant, but at this point I’m starting to wonder what non-meteoric kerisses have in them, so you better send a sample of one of them out for testing – there’s another data point (nickel could be a discriminator, but terrestrial nickel is used, too).
Go through that process enough times, you’ll have a great way to graph out any blade, and it will drop into the ‘extra’ or the ‘terrestrial’ field, with an acceptable level of certainty.
But at this time, no one has done that (& published), so we can only speculate – Iridium should be high, that’s how they started thinking the K/T boundary layer was meteorite-related, and that’s got to be more diluted than a keris, it’s geologic in scale
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Some study of the significant element ratios would be in order before you start, so you can cut lab costs, or just bet on iridium and go for it. I think a couple of different element ratios would be better in the long run, though – you’d be able to sort out which meteorites went into which blade, eventually, and avoid unscrupulous iridium smiths (I don’t really think they exist, yet!).
The best place for asteroid paper research:
http://adsabs.harvard.edu/abstract_service.html
Or, get a planetary scientist to take an interest in the project – but they are really swamped in actual meteorites now, so they might be too busy for this esoteric pursuit.
And if you want a piece of this blade’s metal for testing, look out for the positive Boron anomaly – I did the welding with borax flux
