Pull the bolt back, and ease it forward, as you mentioned, where it doesn't want to work. After the bolt has came to a stop and is sitting in battery, then, put pressure behind the bolt handle with you thumb, and give it another push forward, then try and see if it will work.
I'm thinking it still may be a difference in extractor thickness, and by doing this, it will cause the extractor to slightly move under its spring pressure.
Since it worked beforehand, and has been taken down before, without any problems, I would assume the cause is over something that was changed, which would have been the extractor. The trigger guard will have a little slop in it, when everything is outside the stock, and just the trigger guard screw in the receiver extension (recoil block), but it should all draw up tight, once it is all assembled.
Also, there was a change in the extractor above serial number 119,000, so they're two different part numbers. I'm not sure what they changed without trying to look it up.
Let me know what it does, and then I'll look at the Winchester gunsmithing manual on it tomorrow.