I would assume that the side curtains may or may not have been optional when purchasing new but I'd guess that the sockets and therefore the holes and wood blocks would be standard. I have to say that when I got my car on the road I had a couple of sets of side curtain frames and some NOS material to cover one set. I made the effort to apply the covering and polish up the metal decorative strips and had a fairly decent looking pair when done. When I fit the soft top, which came out way better than it should have considering my never having done one before, I found that the side curtains didn't really fit very well (more like not even close). I suspect that was the case when new from the factory at least for the BN1 BN2 years. Regardless I have not once driven with them installed and haven't missed them. I would never intentionally drive my Healey in significant rain. I do have them on the list to make them fit properly but they will not end up looking like the factory jobs. I think the vinyl /leather covering looked great with the flip-up panel but what a pain to use. The sliding panel type of all clear acrylic on the 100-6s didn't look as cool but they seemed to fit better and were at least functional. You can also use the forward socket to fit a mirror.
With regard to the mirror, I have one mounted just at maximum arm reach (at least for me) on the wing ahead of the windshield. I have lost no more than 2 hats on the freeway thinking I could reach out and tweak the mirror while driving at 65. If I had the mirror in the door socket I'd still have my hats. Lose one hat and shame on me; lose a second had and shame on me a bunch more. I will still tweak the mirror while driving if below about 30 or if I turn my baseball cap around. The latter is a look I do not favor, especially in the Healey. Reference my post on the look of a Healey driver.....