Looking for advise on purchasing a used bike but there is no red key or code card?

What model are you looking at?
Its not the end of the world if you don't have the pin, and there are ways to get either the pin or replacements (but they cost).

The code can be acquired. There are several 3rd party companies that will do it. They will required the cluster though. If you are the brave type, you can open the cluster and remove the chip that contains the immo code. A dump of the chip will give the data (it is not encrypted).
If you're not the brave type then its about $500 to send it away, or you have to purchase a new cluster from the dealer. They don't keep the codes at any level.
I purchased a bike from an insurance auction. Got lucky. The dealership name was on the key ring. I contacted them and they knew the bike I had bought. They sent an email to the previous owner and gave him my info. I was able to get the code card from him.