Will I need to re-ring my pistons?

I have a poly 318 in a '67 Fury. The engine was rebuilt about 42,000 miles ago. When I had the heads done, I told the machine shop SPECIFICALLY that I did not want knurled valve guides, I want guide inserts. A while back, I had to pull the intake because of a vacuum leak. While it was apart, I got my light into the intake ports and noticed severe carbon build up on the valves. Sometimes there is white smoke out the tailpipe. That smoke made me suspicious about whether or not the heads were done as I asked. I won't know for sure until I pull them and look for myself. The valve seals look good. My question is, if I find this to be the case and have the heads done correctly, (at a different shop) will I have to re-ring the pistons along with the head work? Would I be be okay to just clean the carbon off and lap them after I get the guides done? Thanks, FABO support group.