I was looking at a vintage Ithaca NID yesterday and when I removed the forend and barrels, the top lever went to the extreme left. I know that the lever on my Ithaca locks to the right when I remove the barrels. When the barrels were on this gun the lever is just to the right. Anything potentially wrong with the gun? Thanks.

It sounds as if the catch for holding the lever over isn't working. Could have a missing spring or other parts broken or missing. I had one Ithaca Flues model on which the bbls would be released prior to the bolt latching, so on opening I had to be sure & push the lever to the end of is travel to the right to ensure the lever locked over. There would be no particular hazard to using this gun, except one would have to remember & push over the lever to retract the bolts prior to closing it.
I am not familar enough with all the eraly Ithaca models, pre Flues, as to say if they all had lever latches or not. Some doubles do not, on these the lever will normally be cammed over in closing. If on closing this gun you have to manually push the lever over to close, then it should have the latch.

The NID use a rotary bolt. It is designed to latch the lever to the extreme right upon openning. Closing it on the rotary bolt with a little gusto could damage the bolt since it has a rather small section of the rotary bolt that catches the barrel extension.

I know very little on Ithaca's, but using the rotary bolt that is used on the L.C. Smith, if the spring loaded detent is pushed down, the top lever will move past center to the left. It will go farther because as Chuck stated, the barrels top rib entension is not there to stop it.

Why the top lever moved to the left upon removing barrels could be that the spring below the detent is broken and not letting the dedent hold it's place on the rotary bolt and to hold the top lever to the right

I have some new information on this Ithaca. I was way off on the year and model. I call the gun ship and the serial # is 206,817, which puts it as a 1911 Flues model I think. In that case, I assume the lever should lock to the right upon removing the barrels? Would this be an expensive fix? Thanks.

If it's a Flues, take the bbls off and look straight down into the action from the top of the breech.

You should see the locking bolt just sticking out if the lever is returned to the center.
Pull the lever over as if opening the gun and just below it you should see a semi-circular disc.
Actually you can see the 'disc' even with the bolt forward.

That semi circular thing is the barrel latch.
The barrel lug hits that upon closing to release the lever from the 'locked to the right' open position.

It is supposed to be spring loaded (small coil spring) so it pops upwards slightly and locks the bolt and the top lever open when the bbls are dropped open.

If the barrel latch is there,,it may be only the small generic coil spring missing. Or it could be there but gummed up or rusted in place and not doing it's job.
Push down on it with a small screwdriver and see if it has spring tension movement up and down. It won't be alot,,perhaps a 1/16",,maybe a little more (so scientific).

Sometimes the small notch in the underside of the bolt itself that it snaps into is worn and it doesn't catch securely to hold things open.

Takeing the bottom plate (trigger plate) off will reveal alot.
The bbl catch and spring if they are there drop right out w/ the bottom plate off. You can also inspect the notch in the bolt, clean it out, lube, ect. But removing the bolt itself to repair it if needed/worn is more involved.

Its old and there for probobly worn .Almost certainly needs a visit to the "doctor". May be nothing much but without stripping down all else is guess work.