Your gun was made in 1926. Ealry A-5 shotguns were available in 4 grades with Grade I being a plain gun and a Grade 4 having fancy wood and the most engraving on the receiver. The Blue Book values for your gun are:
Add 20% to 30% for retail prices
Following are pictures of the 4 grades that you can use to determine which you have.
I hope this helps you,