Problem with straight lug Speedys has always been finding a modern bracelet to fit - with no help forthcoming from Omega either..... And, not everyone wants to use the very nasty, cheap, but admittedly original, flat, stretch bracelets (7912, 1039, etc).
Dedicated research cross referencing from within the infamous Omega 'redbook' has unearthed that the 1125 bracelet with 617 end pieces not only fits the straight lug Speedmasters it is THE end piece for the case. At last we know now.
The 1125 is an old school style bracelet with the bent steel end pieces, the simple clasp with the big Omega logo stamped in and the cheesy authentic vintage rattle. It's more comfortable than my modern Speedmaster bracelet found on the modern Moonwatch (3570.50) due to more flexibility (a bit like a Seiko or Rolex Jubilee) and not least because it does not have the slab effect created by the solid end links. It's da schnizzle 19mm solution we've been waiting for. It's still available new, but maybe not for long.