Correct on the numbers,none left the factory with matching numbers,they just grabbed out of the parts bins what they had on hand,they did record what was put in each rifle and if the rifle you're looking at has just the 4 digit serial number,without a prefix the records are still available,the records for the ones with a prefix were lost.
The one I have has the magazine pinned with a large rivet through the back ,hard to see without taking the stock of the gun,but could be ascertained with a set of dummy rounds.
They are a very unique rifle,shoot very nice and are quite an attention getter at the range!