915 rebuild question

[gocart]

I'm in the middle of rebuilding my '72 915 transmission. I have bought a new synchro hub / dog teeth for my second gear.
The new part does not measure in spec.
I have read that the teeth need to be machined?
Anyone done this or know anything about it?

New synchro ring and dog teeth measures 3.393. Spec is 3.393 -3.407

Thanks,
Gordon