First, by all means measure everything, if the various parts are with in the service limits such as bore, pistons crank etc then yes I'd leave them alone. Simply replace bearings, rings and gaskets.

Now as for the cam 10mm is not that radical, that translates to something like .375 valve lift. I had cam that I wasn't sure about, the local machine shop had a cam doctor so I spent $50 to find out the exact specs...........might be worth it. I suspect what you have is around 260-270 duration which is fine for a street car. If you can gasket match the manifold and clean up the ports do that as well. You appear to have all the parts needed for a pretty good motor. My guess would be around 110HP at the flywheel which will make a 1200 go pretty well.

Now if you need any machining that will clobber the budget very fast, what was going to be just bore the cylinders and balance the rotating assembly ending up being that plus a sleeve, deck the block and turning the crank....................$925 later.