I had a Speedmaster ref 1479 bracelet repaired last year one of the pins broke on a link in the middle of the strap, the ones that aren't removable. I took it to a local repairer he used a punch to remove the broken pin and replaced it with a new one. I had taken to a local AD and was told I would have to buy a new strap, in the end it cost me £20.00 for the repair.
The pins do wear when dirt and grit gets between the links if yours are worn it would give the impression of a loose link. I think any good repairer would be able to sort it out and no need for a expensive service, don't take it to a AD as most will probably try the "we'll have to send it to Omega line" or in my case "you need a new bracelet"