Good morning Broken Spring: Well first year guns usually command a premium over 2nd year and beyond guns. Lets face it there are only about 5000 of them period. Down side , that's before the solid rib, checkered stocks etc. Being a low 3 digit S/N I would add 20% right off the top. Still being a 2 1/2 inch chamber is good since many early Md 1912/12s were opened up.
Since the serial number on the receiver extention is very faint, and not being able to see the gun, it could be faint from carrying, or possibly being reblued sometime during it's 94 year life. If it was reblued, that will hurt.
Also when the gun left the factory it came with what's known as the "Perch Belly" butt stock. Small pistol grip, long wrist, or possibly an English straight grip. If the butt stock has been replaced, deduct $100.
Now value is subjective. There are Md 1912/12 lovers out there who would really like a first year gun! They are the ones who will pay the price. If your gun is in average condition for a 94 year old field gun with no rusat or pits, in original condition, (not reblued) conservatively $700-$800 today. I would have to see some good pictures to tell you much more. For insurance purposes $1000, simply because if it's ever lost or stolen, your time to find another 3 digit Md 1912 wil take time, and time is money! Most home owners policys will cover "sporting goods" which firearms fall under up to $2499 for an individual gun. Over $2500. they will require a letter of appraisal! The basic coverage is usually $5000 for sporting goods, this can usually be increased to $10,000. for a small fee. If the total value of your guns exceeds $10,000 along with your other sporting goods, you may want to consider a "ryder policy". This is a separate policy not subject to your deductible and can have jewelery, guns, coins, etc listed on it. Generally about $2.00 for every $100s of coverage. (IE: $100 would provide $5000 in coverage).
Regards Dave
Regards Dave