The last finecast model I had a problem with was only a few months ago. It had sat on my own shelf for a very long time (years, perhaps?), and was not a correctable issue. I didn't want to return it to a store, because frankly, I wasn't sure which store I bought it from. I emailed
GW at the address on their website, attached a picture of the faulty part; a real person telephoned me the next day, asked for the batch number off the blister for their reporting purposes, and then couriered me a brand new (complete) model.
Anyhow, my point... if it's not up to snuff, complain to
GW, and they'll send you another

The replacement was beautiful, by the way.
It all has to do with whether the model you receive was created at the beginning or end of the mold's life cycle, unfortunately.