Maybe get it to turnbull to sort it out.? They restored it. Only makes sense.

That's just too much common sense. Problem is, the restoration was several decades ago.

I can take a look at it for you . I make and install all of the ejector parts

Look at it this way. If it is a virtually unfired restoration, the likely they were never quite right at the time the work was completed. Maybe not.
Not that I am suggesting that they would do warranty work decades later of course.

Just that they would be completely capable of tuning them up for you.

I'm thinking about selling this gun, and will probably sell as-is. Disclose the issue, and reduce the price appropriately.
How much should I deduct for this?