Michael there are no records of when these guns were made but in 1884 the serial numbers started at 10000. Also it is hard to speculate if the serial numbers were sequential, but I believe that your gun was made either in late 1884 or early 1885.
The lowest grade was the Quality F and the Quality E had some engraving, finer checkering and had Fine Damascus barrels. The highest grade was the Quality AA and there are only a couple known and one of which I have the serial number to.
Finding a hammer is going to be tough but I would keep looking at eBay for one as they do show up there at times. That style hammer would be the Type 1 and was used until 1896 around serial number 545xx,

If you would be so kind as to mention the gauge and barrel length I would appreciate it for my records, thanks.