I left them alone even though they're not pretty. If that area leaks, and it is very common for it to do so, you are going to get water down the bulkhead and it will eventually rot it at the bottom. Likely it will come down the back of the chainplate and it is very hard to detect without looking at the bottom. I would not put anything there that would in any way restrict the ability to see what's going on and allow the water to drain down quickly where it can be caught early enough to avoid major bulkhead damage. This is an area to check every few days, IMHO. I'll trade form for function any time it means I can keep my boat healthy.

Josh,
A small piece of teak attached with a dab of silicone would dress it up nicely, and be easily removed in the future. Just a thought.

I agree with Bud in the sense that you want the seal to be at the TOP of the deck, and you want the inside of the opening to stay open so that any eventual leakage will become evident. You will want to rebed the top seal at that time.

That doesn't mean you can't still make it look prettier. A block of teak like Tom suggested could be installed so as to hide the hole and still allow a leak to show.

You might be able to use 3/4" teak 1/4 round along the top of the bulkhead where it meets the deck. Notch it out around the chainplate but, as pointed out already, do not seal it, so any leak will become apparent.

My upper chainplates leaked like a sieve from the factory. The varnish along the top of the bulkheads was damaged and the dealer covered them with teak strips, which look fine. There was a small delaminated section at the base near the head, which they also repaired. Evidently, whoever resealed the chainplate at the deck didn't know what they were doing, as I had to pull them and reseal them myself; they haven't leaked since and I have resealed on the outside with butyl tape as extra insurance.

My boat has teak 1/4 round molding hiding that cutout on the inside.