Yes, they're Goodyear welted. The construction quality isn't the greatest (see the stitching) but you get what you pay for. I don't know if I'd say slim -- they are only offered in wide sizing. But I threw a thick insole in there and they fit fine and I have medium to narrow feet.
For $145 I'd say they're a good value and fun to watch the patina develop. Someone in Fedora Lounge posted theirs that have more wear: