Anyone for a novice to be able to tell from home what gauge it is?

Impossible to do with the pictures.





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The PGCA has no records whatsoever of that serial number.
In fact, as stated earlier in this thread 1844 (probably a typo) is the earliest gun in the existing records.

You’ll need to have the chambers and bores accurately measured in thousandths of an inch.



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Take a ruler and hold it across the muzzle to measure the inside diameter. If its around 3/4 " =/- 1/16 its probably a 12 ga. If its closer to 5/8" its probably a 16 ga. If you have more sophisticated measuring devices, the muzzle diameter of a full choke 12 ga. is usually around .700 and a 16 ga. around .635, ususally within 10 thousandths either way. FWIW

Grab some spent 12 and 16 hulls and start trying them on for size.

Hopefully this helps, I removed the forend and took a picture of two different areas that have markings/numbers, the serial on the receiver, and numbers under the forend. What I found interesting is the serial number under the forend is in the wood and matches the receiver but there is also another number in the metal.

The number on the barrel flat is the order number, not the serial number.





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pics
 

pics of the markings

Try taking other pictures. The only one in focus is the one in the wood.





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Regardless what gauge it turns out to be, it appears to be in very nice condition, and very early.
As I recall, Jay Oliver has a couple of the earliest known. He’ll chime in here, I’m sure.