A nice family heirloom. I'm glad that it has stayed in the family.There is LOTS of information available on line about Henry E Leman and his enterprise. A good starting point is the attached article. There are many guns with Leman locks that were sold commercially and used by other gun builders.. However when a gun is found that also has one of Leman's stampings on the barrel, the gun was typically made in his shop. He made many different styles of flint and then later percussion guns. so the lack of a patchbox is no surprise
If you photograph the rifle on a darker background it will show details much better. Not BLACK but, grey , tan, etc.
There is LOTS of information available on line about Henry E Leman and his enterprise. A good starting point is the attached article.