I agree with Boris Badinov's suggestion that the bolt is of Chinese origin. And I also agree that more than likely, the rifle's serial number was derived from the serial number on the bolt. I don't think the receiver is anything other than Albanian that was scrubbed. I can see no evidence of the stock ferule being replaced and repositioned, or the removal of the FSB or Gas Block. My biggest question is, why scrub the original serial number, at all? Just seems odd, but anything can happen in the SKS world.
I'm not familiar enough with the early Chinese and Russian bolt carriers to decide which this is. Are there examples of early Chinese bolt carriers with the proof marks like this? We don't know if these rifles were "assembled" here or in Albania. If it was in Albania, were there supplies of Russian SKS parts for reuse? I know the Chinese parts were used frequently for repairs in Albania. If they were put together here, anything is possible.
I don't know what to make of the measurements you reported. I used a set of dial calipers on my '69 Alby and two different non-scrubbed Chinese receivers. All three came in about 1.251"-1.252". Without a proper OD gauge I can't get much more accurate. I'd think that receiver scrubbing would take at least .020"-.030", or more, off the total width?
The receiver cover could have been one of the non-marked replacement covers that were available for a good while, and marked to match the rest. It doesn't have the "stripe" across the back like most original Alby and Chinese covers.
firstchoice