Yes, after market and was being sold by a vendor on EBay. It's the same bracelet that comes with the Seiko SPB051.
Bought new from my local AD on Saturday , was walking past & the blue bay 58 just shouted out to me from behind the toughened glass . “Buy me ,buy me ,make me yours , I’ll look so good on your wrist “ or I think that’s what I heard . Anyway I went in & asked if I could try it on , no problem at all I’ll just get it for you , then I heard “ oh this is a display model only & doesn’t work but you can be added to our waiting list if you want to be . Slightly disappointed by that ,I said I’ll still try it on please & check out the fit . Then the Manager came over & said that’s a lovely watch , I said yes it is but you haven’t any for sale as I would have bought it , He then said that they had just took delivery of 3 that morning and did I want one . Yes I do ,thank you very much & the deal was done .And think it compliments my 79090 nicely .
I'll play my Seiko Coctail Presage LE for now, I'm awaiting for my blue dial Orient Kamasu coming tomorrow.