I'll take a stab at the age. Circa 1892. LINDNER !!!!!! removed the crown from the crossed pistols in 1891 due to the new German laws. About a year was given for the dust to settle before he had a stamp that had the pistols and HAL over on that same stamp. During that time, he used two separate stamps. The pistols and then another with HAL.
Looking at these pics, I think I see that the barrel stamps are not duplicates.
Ken Georgi will be along to set me straight.LOL
As to value---few hundreds toward the low end. I would be interested as a parts gun or might stretch to restore it out of love. It is a very low grade and never will command much.
Best,
John

Humble member of the League of Extraodinary Gentlemen (LEG). Joined 14 March, 2006. Member #1.