I wandered in here looking for Ithaca information. Found a few posts about serial numbers and pre-war Ithacas. I had the same trouble as other members - couldn't find out an exact address to e-mail Ithaca for information on a side by side boxlock I just purchased. 
It's a clean sport grade marked "smokeless powder" on the barrels. Double trigger. Only marks at the action are the serial no. 110988 and "S12".
Looks like a good clean hunter. I wanted a more comfortable field gun for pheasant. I gave my Win' Model 12 to my son last pheasant season to make his hunt better. Tried to use my Rem'870 but it cocked my wrist at an uncomfortable angle when carried for long distances. This Ithaca has great classic lines and I won't feel too bad hunting it in heavy brush... unless it's worth more than I think. My guess is the $380 I paid for it might be a little on the high side. But it was very clean, good checkering and good color and wood. Very basic engraving, nothing fancy.
I'm a fairly good machinist/gunsmith and usually take apart an old gun as soon as I get it home. This one felt just a little stiff in the firing pins but didn't want to take it apart until I found some literature on boxlocks. (Did I guess right? From what I've found I think this is a boxlock) This is my first s-s and I'd like to take care of it. 
Any assistance with dating this and sources for maintenace would be appeciated.

Those old Ithaca box locks are just about bomb proof.  About the only problem I have ever seen them have for wear was the cocking bar wearing off too short to actuate the cocking mechanism.  Disassembly/reassembly can be a bit of a hassle, so I wouldn't do it unless I had to.  It IS easy enough to take the buttplate off the back and remove the buttstock to access the whole box lock mechanism.  Clean that and lightly oil and you should be good to go.  Be careful to keep that drawbolt tight so the butt stock doesn't wobble on you.  

If the barrels get loose on the receiver, tightening them is a pretty major job for the amateur, but straightforward for the well trained and equipped gunsmith.  Other than that, there isn't too much to do other than standard cleaning and lubricating.  One caution...Do NOT dryfire without snap caps.  The firing pins are harder to replace than they ought to be!

HTH, Froggie

PS  I'm not sure Ithaca is still actively in business, hence the lack of a website.  Dixie Gun Works catalogs used to have a serial number list for the old Ithacas in their appendix section each year..you might look there for that bit of info.

Going by the serial number you have yourself an Ithaca Knick model made in 1922. Very nice guns... absolute workhorses being very reliable.

I have two Ithaca doubles from 1911 and 1921. Both of mine are Flues models but are very simular to the Knick as far as I can tell.

Here's my older one... enjoy yours, they are sweet to shoot.

Regards,

Darryl

"Building Double Rifles On Shotgun Actions" by W. Ellis Brown and published by Bunduki Publishing; 39384 W.C.R. 19; Ft. Collins, CO 80524 has a good description of how to dismantle and reassemble box lock action as well as how to make the tool to ease the job. I bought mine online. Google around and you will find it.

Bill

I've got the book on order for future reference. Brownells has the best price from the couple of sources I'd found. Took it to the trap range yesterday for my first chance to shoot it. Turned out to be a great fit and a fun shooter. Looking forward to the last weeks of quail season here in Texas. Thanks again for the help guys.
PS - Great Forum! Hats off to all the people working this site. Looking forward to future visits.