Should it squeak ?

I recently purchased an SMC F 50mm f1.7 from eBay. I paid a fair price based on what I have seen advertised here.
The problem I have is that the iris 'squeaks' when it closes both when stopping down whilst shooting in A mode and when the lever is moved when off camera.
The seller has been very reasonable and has said that it did that whilst he used it and that he will refund the item if I wish to - so I have no issue with the seller.
I expect that the noise may come from the spring controlling the iris blades. Had I purchased this at a bargain price I would be inclined to keep it and see how I get on - however having paid the going rate I am inclined to seek a refund.
Before I do this - does anyone have a different view ?
The lens is very sharp with great overall IQ and I am loath to part with it - but it does seem the sensible thing to do- and I have my M model to fall back on.
Regards Gary

Why not phone up a repair house and ask them?

I've never heard a squeak but if anyone has it will be someone who repairs lenses.

Drop Alan Marlow at A.M technical services an email and see what he say's.

in my experience, unless "it" is a mouse, the answer to this question is almost always "no"

If the squeeking wasn't mentioned in the original sale and the seller is a reasonable person there might be some milage in exploring a partial refund, after all he's already acknowledged that it did it while he had it.