I have just been through something similar.
I have a ser 3 33 with plastic fag bearings and Eibach springs.
I also have ser 1 or 2 struts with koni inserts with the metal roller type bearing, I have both types of metal bearings, one from a sud and one from a 33 and both types of strut pans.
The strut pans from my ser 3 are the same as I have for my ser 1 or 2 struts and inserts. There is another type of metal roller bearing that is from a sud which has a lip for the dust gaiter, the hole in the spring pan is also larger as the lip for the dust gaiter is now on the bearing not the spring pan.
I fitted my ser 1 or 2 struts using the same spring pan and top parts from my ser 3. There was increased negative camber and the steering arms were too long and I couldn’t adjust the tracking inward enough.
I have been told that there is a difference with the steering arms and that I need a ser 3 without the adjusters.
You may have the opposite problem if you do fit the plastic bearing strut, as in the steering arms maybe too short and you may end up with positive camber.
When you look at the struts, they look the same, the holes in the flag for the hub, the level of the spring pan when it is sitting on the bearing and the steering arms possition all look to be the same.
I am just saying this in case you fit the plastic type strut to find problems with your steering arms.
I can take pics of the strut pans and different bearings fitting into the same spring pan if you want.
Can you show us a pic of your strut pan?
If i were you would do as mark suggested and use your old struts with Koni inserts, if you can get some.
The plastic fag bearings are crap, all the racers use the early type struts with metal roller type bearings as they are are stronger than the plastic ones which crack as soon as you lower the car.
Is this of any use?