Acutually, the call to signed32 will depend on the behavior of the Flexlm. For example, if the crypt filter is used, the code will skip the call to signed32. They have improved the security in a way, and does not provide compatibility in this special case.
On the other hand, it is a better idea to recover the seed from the job structure, which envolves identify the call to l_sg and record the memory contents. There has been essay's and calc tools to make this very easy. Most important is all the behavior can be defeated in this way. Of course, we are not talking about the ECC.
If you have identified the l_string_key code, you will be able to found the license key information by just looking at the return point of this function. There will be a call to atox, which convert and format the license key in ASCII format, just check the return value in EAX, do a reference to the memory, and dump the key. It is automatically generated for you. There is a easy signature of the atox function, there is a long string 0123456789ABCDEF defined there. Do a search on the code, you will find it easily. Then you can trace back to the point for the key generation. There is no need to recovery seeds, no need to run license generation.