Water Table numbers

[Johnnyray73]

I have just gotten an 1889 Remington SxS that's a grade 3 with serial no. 61064. There is another number on the water table a 51 and it is also craved lightly on the stocked. Does anyone know what it means. Also, how can I tell if it's a 10 or 12 gauge.

Thanks
Johnny

[RemRB]

Need a little more info. When you say "carved lightly on the stock" is that normal checkering or someone actually carved something on it? The number 51 is an assembly number, you might see that same number on the inside iron of the forend. Guess you would have to get a fired 12 gauge empty shell and see how it fits the chamber. What is the barrel length?