Can a CNG converted vehicle still run gasoline?
I'm looking at an old AT&T Chevrolet Express cargo van at an auction yard and noticed that it says it runs off of CNG. On the side of the van above the original gas fill location, there seems to be the place to fill using CNG. I'm assuming this was a conversion and didn't come from Chevrolet this way. Unfortunately, I cannot see who did the conversion so I cannot contact that company directly. I have seen some Ford trucks that can either accept traditional fuel as well as CNG, so my concern is whether or not this old AT&T van can accept both. There aren't many CNG stations near me in central California, so I wouldn't want to be solely dedicated to CNG. Also how hard, if possible, would it be to just remove the kit altogether and return back to a traditional fuel vehicle?
The van is about 4 hours away from me, so looking at it in person isn't possible without making the drive (which I will do on auction day if I decide to buy it). Just didn't want to make the drive unless I knew I wanted it once I figure out if it is gas compatible.