What are the differences between a standard Bravo transom assembly and the Seacore transom assembly? Also does the Seacore assembly have stainless transom studs? Is the seacore worth the extra money?

Unaware if there are any structural differences. Seacore as far as I know is an extra corrosion protection package.
Stainless studs? Call Mercury maybe

Yes the seacore has stainless studs. Also a stainless upper shaft. In addition the castings are hard anodized under the paint. Imo well worth the extra cost.

https://www.mercruiserparts.com/bam/...30969/11210/60
https://www.mercruiserparts.com/bam/...30969/11210/70

Thank you for the information. I had recently purchased an HD transom assembly, but when I received it, it had stainless transom studs. I was surprised to see that, and it made me question if the unit I had received was a seacore unit. I just spoke with a tech at mercruiser who was very helpful. I gave him the serial number and he told me that the assembly I had was not a seacore, but an HD version that was built in Feb 2021. When I questioned him about the stainless studs he said that Mercury was starting to put more stainless into their assemblies. He also said that my unit should have the stainless pin even though it is not a seacore unit. My conversation with him was very informative.