Hello, does the coil come out with taking one bolt in the back sort of unseen? Wanted to clean the terminals up file and sand.

Yep. Just took mine out an hour ago.
10mm wrench. Use the box end, you can feel the bolt head but cannot see it.
Loosen it up a few turns, then the omega shape bracket will be loose enough for the coil to slide out.

Thanks Steve, just took it out and cleaned up the terminals where ever I could. Can anyone tell me what effect this might have? To be more clear if you had bad connections to the coil what are some of the problems you might have?

If you have it out and don’t know how old it is, it might be time to replace.

Bosch blue coil still the recommendation?

I believe so but there appears to be an issue dependant where they are made,don't remember exactly but never had an issue with the older ones,running a Beru blue on current build seems fine,$23 on Amazon.

They are reliable for the most applications; I replaced my old blue with a new one when the 1-2-3 Ignition was installed at the recommendation of 1-2-3.
Coils can be bench tested; a search will bring up the thread