Question 1;
I'm replacing everything on the transom assemblies and so far everything has made sense and been easy to get. However, in the parts diagram for the drive oil reservoir fitting, # 2 shows it as an O-ring. (Part # 201951 or 25-201951) I google the part number and all the pictures I see it looks like a rubber O-ring. My original is a hard fiber washer. O-rings are designed to be in a channel for proper sealing, not squashed against two flat surfaces with a lock nut. Is there an alternate part number, or are all of the google images wrong? Maybe this is a hard rubber?
https://www.mercruiserparts.com/bam/.../30966/952/180

Question 2;
I read somewhere the split in the two upper bushings go in a certain clock position. Is this true? If so, let's say the bow is 12 o'clock, stern is 6 o'clock. What "time" do I arrange the split.

what is the serial # of the gimbal? merc made some changes along the way

so looking at the various diagrams my guess is merc changed to a o-ring along the way. I have run across plenty of applications where an o-ring was just on the shaft and pulled down to squish is flat so may be they thought that was better than just a fiber washer that may not seal well?

There is no number on the decal, but according to the 1990 build sheet the drive serial # OC828641.

I see the number was superseded from # 20195, maybe that's the answer to my question.