The adventures of Tom Sawyer sentence meaning

What does this phrase from The adventures of Tom Sawyer sentence mean: "True, the knife would not cut anything, but it was a "sure-enough" Barlow, and there was inconceivable grandeur in that -- though where the Western boys ever got the idea that such a weapon could possibly be counterfeited to its injury is an imposing mystery and will always remain so, perhaps."

Thank you!

Solution 1:

The Barlow knife in question was an inexpensive and substandard knife¹. The boys were very excited to have a genuine Barlow. However, a counterfeit Barlow could not possibly have been a worse knife; thus the knife could not have been "counterfeited to its injury".

¹ I assume Barlow also made better knives.