Hi there,
no, it should be fairly standard. I expect it has the same threads as 1Z, AAZ, JX etc. It's a JX mount i'm trying to bolt to it anyway.
I presume these bolt holes arent used when the engine is in a (rabbit?) golf, so this is maybe why the holes are gunked up. Probably is m10x1.5 as you say, was just hoping to have it confirmed before I buy a tap to clean the threads up with.
I'll try and post up a pic this evening when i get home.
Cheers,
Monkey Phil