Your gun is a Grade 2 lifter action.
It does look to me to be a 12g. But only you can check it out and confirm.
Your serial number is not in the book.
Which means that there is likely not stock book records on your gun.
I did put your serial number into he PGCA research letter database page and it indicates that there IS records on your gun. Likely just order book records. But that means a research letter can be provided for your gun.

These early grade 2 guns with the sculpted bolsters are great!

8142 is probably the order number for your gun. You'll see when you get your PGCA letter if you ask the researcher for this information. He will not normally give you the order number, so ask. The 4 4 is the unstruck barrel weight, which pretty much means it is a 12 gauge gun. The D means Damascus barrels. I don't know what the 526 means, but someone here might. The U on the water table is the catalog grade of the gun. The U is normally a Zero grade gun, but the sculptured breech balls and Damascus barrels indicate a higher grade gun as a previous poster suggests. The water table marking is apparently a factory error. This is some great gun.

which ever gauge- a great gun in great condition, many of these have issue at the top of the stock head.

less than 100 numbers after the very plain U marked 10 bore lifter I have, but very obviously this one is a better grade gun.

very nice

I can't thank you enough for all the replies and information. I really appreciate your time fellas!

I'm going to go check the bore size today and take pics of the barrel.

I have no experience with SxS shotguns and 100+ year old guns. I'm actually surprised that this gun is considered in good condition. It had been stored for 50 years or so. it does have some minor rust issues that i would like to clean up but frankly I'm afraid to touch it now! Being in L.I., NY it seems that upstate and Conn. have plenty of qualified Parker gunsmiths that I can get to so I don't mess anything up.
Heres a picture of the breach (excuse my terminology if it's incorrect). I will take some shots of the inside of the barrel today

Is this pitting typical for a shotgun this age? Is there anyone out here with shotguns of this age that are shooters, or are most considered too dangerous?

If you feel like a trip up to Rochester, I would be more than willing to take a look at the gun for you.

many of them are shooters still, many are not.

A gun needs to be evaluated by someone who knows their trade for condition before firing.

The 12 gauge load fit and the cap fit the extractor (which I did not know it had until I put the gun together!), but 12 gauge seemed loose, so I went down to the local shop and tried a 10 ga. and that didn't fit so I guess it's a 12. The 12 ga. load was an old paper style so maybe that's why it was a loose fit? I could literally drop the shell in with no resistance. I'm not very knowledgable with shotguns, but if it was a rifle, I would immediately think something was wrong with the cartridge.
Thanks Brian, I will be ice fishing on the St. Lawrence in Feb, and I may take you up on that offer! I saw some great work you do on your website, and if I decide to keep it, it would definitely need help with the forend as its well worn.

I have no. 14830, a 12 gauge G (2) grade, same as yours. Mine also has the 526 mark on the watertable. I have seen that mark and 524 on a number of lifters in this serial number range and I believe them to be inspection marks.

Thanks again guys for all the help and information! I now know more (i think) than my dad knew about what was hiding in the attic all these years!

Next paycheck is a membership and research letter for sure. I guess I should then be able to figure a value for this piece of American history.

Given the great experience I had with all the help, I could use some guidance on starting research on the other side by sides I inherited. The ithica, barker ( both early hammer guns), and the Belgian made sSxS's. what's the recommended places to get info on these guns? Are most of you Parker purists, or do you occasionally stray to other makes:)
I'd be inclined to stay here with the friendly helpful folks, but any guidance in researching the others would be appreciated!

Geoff,
You can certainly post on your other guns in the "other fine doubles" section of this site.
Also, feel free to send me particulars directly if you wish. I could assist in telling you what I can.
In regards to value on your Parker that you discuss here, it is very difficult to say for sure without a thorough evaluation of condition. Especially since your gun seems to be in good shape. It is not a run of the mill $500 beater by any means.