Bought a very nice P228 that the owner had put Legend sights on, they work great except they are 2" low at 10m. This is totally normal for me I have found but would like to swap them out.

So what is the stock P229 legend front sight height?

Legend?
No matter what it is there is no set in stone sight sets.
I have seen all kinds of combos with the 228 and 229 in 9mm.
What does it have now? It can be a #6 or #8.
If it's a #6 then a #8 should get you where you want.
This is a good read and has sight # locations.
https://www.realgunreviews.com...ights-sight-numbers/

That link is excellent and reminds me how much I love Von Stavenhagen sights.

I've found I prefer 8/8 sights on all my SIGs regardless of caliber...save for my P365 which IIRC has 6/8, but for some reason that one seems to work just dandy for me.

Are the sights not marked/stamped on the Legend sights? Was it a Legend or Legion model he got the sights from? Depending on which model the sights came from is questionable. I say that as some sights,depending on caliber, if I am not mistaken, can be a #8 or a #6 height.

I replaced the #6 front sight on my P365 to a #8 and now it is dead on where I am shooting. I had the same problem as you do with it shooting low. the sights on my 365 were stamped so that made it easier to figure out.