Certainly not an expert, but I didn’t think gas ranges require venting if they are used for cooking. What do the instructions say?
I have a gas stove and the house had one when I moved in (which I replaced with my current stove). IT IS NOT VENTED.
That being said, my house was built in 1910 and building codes, even if the DID exist in 1910, have changed over the years.
How do you even vent a gas stove? As far as I know, you can’t. The oven vents to the outside (i.e the kithen) just above the cooktop, where the hot gasses can become a convenient plastic container melter. And the cooktop burners can’t be vented - practically speaking - because the flame is under a bunch of pots with food in them.
Are you talking about the vent hood? With the light and fan that can be manually switched on and off? These come in two styles. One style vents to the outside and the second style just blows the cooking odors and moisture back out into the room after running them though a charcoal and aluminum mesh filter. A grease trap and not much more.
I don’t believe the second style is up to modern codes (i.e. code now requires that it be vented outsided), but often older houses are grandfathered in based on the fact that they are old.