iso bolt question

i just had a replacement lower manifold installed and obviously the gaskets were replaced. i am not sure if the mechanic used the new bolts or not. if i open the upper plenum to check can i swap the bolts out one by one so i dont have to replace the gaskets again. how tight should the bolts be if i do replace them

The bolts that hold the LOWER intake manifold in place are re-usable.
I would NOT remove the lower intake manifold bolts.....just leave them in place.

The bolts that get replaced on the 1999 and newer are the "isolator" bolts.
These are for holding the UPPER intake manifold to the lower intake manifold.
They are a bolt with a rubber-type sleeve on them......the black ones break down after long term exposure to oil........so there is a improved bolt that has a green colored sleeve that holds up to oil, and maintains the upper part of the upper intake manifold's firm seating to the lower (black) part of the upper intake manifold.......preventing vaccum leaks.

The BEST information that I have found on this is in THIS post that contains very clear pictures and instructions.
The ISOLATOR bolts are the ones that you see when you lift the upper part of the upper intake manifold off.......shown with red circles around the 8 bolts.
http://leckemby.net/windstar/windstar01.html

Sorry for being unclear. I was talking of the bolts holding the upper to the lower. I am not sure if my mechanic swapper these out when i had the new lower manifols installed. if i remove the top half of the upper will i be able to tell if bolts are new just by looking at them if they are already installed? If i need new ones can i just take out one and install a new one, one at a time? i know the gasket are all new and dont want to remove the whole upper intake or disturb new gasket at all.

I am guessing that you can......look at the pictures in the link I posted........if the bushing (isolator) on the bolt is green, you are OK......if it is black, then it is the old type that needs replacing.