Sounds like you're looking at a Record Model IAB. Gun was manufactured by IAB in Marcheno, Italy until the mid 80s. The base gun is a striker fired action with extremely fast lock time. Some of us diehards still shoot the gun. I have a modest inventory of spare parts which I have recently expanded. If you buy the gun, let me know at the email above and I will send you a parts diagram and assembly/disassembly instructions in English. Depending on condition, a Record Over/Under should sell for $500.00 to $700.00. The combo with an unsingle barrel and an O/U in the Record Model typically sells for around $1000.00 and up.
Hope this helps. Mike Mann White Creek Gunstock Blanks LLC Your Myrtlewood Source.