This may be a stupid question but here goes anyway.

Do metal bolt in tyre valves need to be replaced when replacing tyres?

Cheers

No, they last for years..... In truth even the rubber ones don't need to be replaced but it's possible during the tyre removal the seal will break offering a slow leak, so preempting this they are replaced.

My flush ones are still going strong after 3 years

Tony is correct on that one as I found out to my cost last month!
In my view it wouldn't do any harm to replace the O rings with every tyre change to save problems later.
h

That would be labor intensive to be honest and some customers might think their being done over...... I agree though that the seals should be changed.

Another stupid question. Where are the seals? would the valve need to be unbolted to replace them or are they on the removeable inner valve?

Cheers

Yes, the valve has rubber O rings top and bottom of the anchor points, over time these perish developing a slow leak.

My metal valves in the Ray's have lasted over four years- unless theseals got replaced when the rims were refurbished - Tony?

We change them because the valves are removed for the refurb.