All Ithaca Gun Company models with seven-digit serial numbers were manufactured in 1968 and 1969, before they changed to a different identifying scheme. The serial number indicates your Model 37 was made in 1969.
1950
There's a list of serial numbers by year at http://ithacagunrepair.com/page5/page23/
The M37 was mge in 1949. Value depends on the condition and gauge, as a 20 would be worth more than a 12.
It is a 10 gauge if it has a damascus barrel and it in mint condition can be worth up to 2000 bucks
1912
i saw a used one on ebay but you can contact Ithaca Gun Co. directly
1951
The recommended gauge for a 100 amp SER cable installation is typically 2 AWG (American Wire Gauge).
Made in 1955
100-500 USD
1917 if it is a sxs double
100-1000 or more depending on specifics