If I cut the 2 bolts that are holding these two sections together will they come apart or is there a pipe in pipe scenario here?

I've been on this form for about 10 years but I had to create a new user ID bc Password reset does not seem to be working.

Welcome to CF.

We need more info on the vehicle. Looks to be a donut gasket in between.

Yes you can cut them and it will come apart.

Go with longer ones when u replace the bolts. Hella easier to get back together.

Cutting will separate the two parts, but I don't believe that the head of the bolts rotates. Are you replacing the down pipes or are you replacing the exhaust manifold or are you just replacing the bolts after you cut them? How I'd proceed would depend on which parts are trash. If you are keeping all of the parts, then you'll have to drill the bolts out - provided that my memory is correct.