Originaly,ArmaLite made two variations of the AR-5,the AR-5 and the AR-5A.
The AR-5 has revited sections and used the same M4 survival rifle magazine.
The AR-5A as a machined receiver with no revited sections,the magazine catch/release is front of the trigger,in the trigger guard,and it as the "Ronson Lighter" magazine.
The one in the image is a AR-5,the salesman sample question,if ArmaLite was using a salesman sample it would have a plastic stock as the use of plastic for the stock was one of the basis for ArmaLite technology (at the time),i have no idea of the works used for the magazine catch/release in the AR-15 (the AR-5 as it in fron of the trigger) but in the image there is a lever pice in front of the trigger guard,this was possibly made so the receiver could be used in this stock...?!?
This is the first AR-5 i have ever seen and if only the receiver is original it would be a nice collection pice to have...but for that price...?!?
I am not saying that it is not a original "salesman sample" as i am just speculating...good luck.