I'd think the core file structure and location would be the same across all versions. Let me check my son's installation - he has the GOG versin - and I'll get back to you.
EDIT: No xp1patch.bif in his installation. Looking at the content of the xp1patch.bif from my Gold installation, I see that all the files in that .bif are included in the xp2patch.bif. Therefore, it would appear that if you have HotU installed, you don't need the xp1patch.bif.