We were thinking of putting a new gas stove + electric oven in but it hasn't gone anywhere yet. I had the plumber out for a different job and I knew he was a gas plumber as well so we just asked.

I guess in your situation, that cost of getting the gas from the existing line to the kitchen will be something you have to pay for, either now or when you get the Reno done. If you get it done now, then that's one less expense for the Reno itself.