Jon, not sure the second signature is correct either. I had some examples of AS signature but they ain't there now! The fake Vase I bought from Japan had a decent copy of his signature, he signed only a few best pieces, the signature on my piece is quite small and neat. I have several 'serious' pieces of AS and none of them are signed. Mind you there are pieces fetching 30-60,000 and I don't have any of those!
The bolt is not unusual unless it is steel mostly they are copper rod. Signed in the middle is unusual.
I have a collection of about 15 lamps I have picked up mostly labelled. I got scared re copies at one stage and went for labels as the only semi-safe solution.