C Man,

Your gun (#604) is from the second series of Lindner serial numbers. #796 referred to in the previous post was from the first series. The current theory is that Lindner restarted the serial numbers after the Anson and Deeley patent protection period ran out at around 1889/90. #459 of the second series is the earliest use of the HAL mark, so, just to take a stab at it, Your gun was made circa 1891/2.

Regards
Ken

I prefer wood to plastic, leather to nylon, waxed cotton to Gore-Tex, and split bamboo to graphite.