Thanks for the extensive info.
Looks like all of them come with the wrong pilot brg.... The gasser type bearing is pictured, and it was what I also found in the last 271265 Sachs kit I got. Too bad about that. Looks like the Sachs kit has the right disc but the cover looks quite different from the original -- the fact that it had to be modified to fit over the dowels on the flywheel makes me wonder if it is a gasser cover that they throw into the diesel kit, like with the pilot. Were there any other fitment or operation issues putting it in?
The Sachs number on the OE disc I took out of the car I'm working on (also an '85 wagon) is 18.1861 901 104, similar to but slightly different from the 1851 901 134 you pictured on the 271265 kit box, maybe they updated the disc or the linings slightly, in either case I suspect you are right that that is a good number for the disc. However, using this number, or using any of the *three* Volvo part numbers I have for the disc alone (1220942, 1377326, 3549535), I'm not able to find the disc available by itself. Might just get this one re-lined since the cover and TO bearing are in good shape.