Sherlock Holmes and the Case of the Missing If

In Chapter 13 Part III we read this:
"Gottlieb would have made an excellent Sherlock Holmes -- if anybody who would have made an excellent Sherlock Holmes would have been willing to be a detective."

The Japanese translation is mostly fine, except that the word if is missing.

So, is it a good translation? I guess that depends upon what the definition of the word if is.