Maybe the envelop is cut in half because it was addressed to someone besides Bukowski. If it had been addressed to him, wouldn't the signature half have been kept attached to the address half? Any guesses as to possible legitimate reasons for the cutting? I once sold a real Buk letter that had the signature and drawing cut out. I knew why: my friend, a small press editor, who received the letter, used the original art in the paste up of his magazine. He could have photocopied it and used that for the paste up, saving the letter, but in those days not many were thinking a Buk letter with art would be worth big $$$.
Is'nt FDC's something you arrange with the postal authorities, that normally include lots of envelopes? If there were a bunch of those Buk FDC's out there, we would've have heard of them a long time ago. The guy on the envelope and stamp does'nt even look like Buk, not much, anyway.
Maybe the seller found this FDC and thought the guy looked enough like Buk to pull off a swindle.
I wondered the same thing, Bukfan. I'm no stamp collector, but the FDCs I've seen have only been signed by someone relevant to the subject of the stamp. Why would Buk sign this and draw a picture on it? But then, if it's a forgery, why do it on a First Day Cover? Why not on something related to Bukowski? Maybe no Buk books were handy? Strange. This is an item that definitely needs a back story and some provenance.