When you get a vintage Speedmaster, never, ever, leave it to a Omega Boutique for service. Or another Omega AD...
There's a big risk that they start ripping vintage parts of and replacing them with new.
You need an experienced watchmaker for the service. References for these are all over the forum, depending on where you are located...
My recent full service (no parts needed) for my cal 321 105.012 was 8500 SEK = approx 810 EUR and i think this a quite common pricing