Submariner 16613 Dials

[Alan G]

Hi Guys
Just a quick bit of advice, Can anyone tell me what availability might be and a rough expected guide to price for a 16613 Genuine Blue Dial (new or used), I have a Slate Serti at present and I am considering purchasing a standard Genuine Blue Dial as a spare if they are sensible money, I was once told that if you have a dial change by Rolex in the UK that they keep the old dial but dont know if this is the case, I have also seen comments suggesting that the Serti dial is a diffent fitment to the standard dial , does anyone know if this is true

thanks Alan