Is your MkII Gti mounted upright or at the 50* position the factory used for diesel engines? E D I T - I've now spotted the factory diesel sump in one of the photos so 50*.
The tubular parts of the engine mounts fit in the factory locations and I think might be the early diesel parts. The brackets welded to them for the rubber mounts I am not familiar with but they may be standard early parts.
The twisted steel strip connecting the ally mount arm to the sump is not factory nor appropriate. The sump thread normally carries the front end of a long triangular strip which picks up the other two bosses and then carries the metalastic exhaust mount at the back. The steel and rubber exhaust mounts shown appear custom made.
I suggest that you research the early, non-turbo, diesel mounts and exhaust to confirm that is what you have. If it fits the PB engine OK I think it will also take the AGG. You'll need new rubbers at the very least.
I would be interested in a couple of photos from above. Especially on the left side. Before I did my AGG conversion I considered the PB/MKI engine but found that it needed 'modification' to the nearside chassis rail to clear the inlet manifold. I would like to see what's been done with yours.
Are you aware of the Fb group 'VW T25 GTi conversion club' at
https://www.facebook.com/groups/256191624580607/" onclick="window.open(this.href);return false; ? Lots of good info and answers there.
Hope this helps.