The Record QR No 12 is worth anything from £10 to £150.
If you go down the route of restoring it, the closest paint match is; RAF Roundel Blue.
Were the plate, for the QR normally has C'sunk 1/4 or 3/8 Whit screws holding it in. Yours may have been repaired in the past.
Easily fixed or left along the choice is yours.
The spring and loose it's tension over time, but can be adjusted to work again.
If toy strip it down there pin holding the spring and washer ,ay break or be bent. A split pin can be used as a replacement, but the original pin will be an imperial size.
The jaws look to be in in good condition and should not need to be removed. If you have to. A decent Impact wrench and a slotted bit dress to fit will remove them.
Warm the body up until spit bubbles before you try, plus releasing oil will go a long way.
The fixings holes a bit bigger than 3/4" 19mm, but M12 bolts and washers will fix it firmly to the bench.
If you do decide to restore it as The Yellow Ardvark said, Paragon Paints sell RAF Roundel Blue, but don't do as I did when I restored my Record 83. I bought the gloss finish, it looks much better in matt.
Some ask silly prices on ebay. I saw the larger 114 for sale for £375.
There is a thread over on the Mig Welding Forum, "Show us your bench vices". There are a lot of knowledgeable folks over there.