Did you use a timing light to try to see where the timing is currently set?
I have always been curious about that old "one tooth off" theory. Specifically; how many degrees will the timing actually move if the distributor is stabbed one tooth out of it's proper mesh point with the cam.
Here is what I found:
There are 13 teeth on the distributor drive gear.
So if the distributor is stabbed one tooth out of position, the timing of the spark will be advanced (or retarded as the case may be) about 28 degrees in relation to it's associated post.
There are 8 posts in the distributor cap spaced evenly around the 360 degree arc.
That works out to 45 degrees of separation between one post to the next.
For the sake of argument, let's say that being one tooth off in the retarded (CW) direction will cause the rotor to be about halfway between the #1 and the #8 post when it fires the #1 plug.
If you look at the spacing of the posts on a 8 cylinder distributor cap, you'll see that it would be easy to rotate the distributor sufficiently to bring the rotor back in line with the #1 post.
That is taking into consideration the fact that the vacuum advance diaphram chamber limits how much the distributor can be rotated.
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The point of all this useless information is that if there is a concern that the distributor was stabbed one tooth off, timing can be brought back to normal without pulling the distributor.
No one would leave it like that. But, as a test, if the engine is running rough, it could be temporarily adjusted to confirm/eliminate improper timing as the cause.