How often do you see those with 21 jewels plug
and it shows as 23 jewels on my end

Not very often on the 1892 models, Peter

see more on the 16s ones, at least I have

Is the Balance wheel cap jewel a Diamond?

That's cool!!! I'd looked for an up-jeweled plugged Waltham but had no luck till I found a 21j Ball-Waltham up-jeweled from 19j.

yes it is diamond
well is one of few or one of many?

That means it was intended to be a 23J and was finished out less the Jeweled Motor Barrel. VERY RARE Peter. Good collectible! I wouldn't be surprised if the Escape wheel also has a diamond cap. Those are capped on both sides, making it a 17J with 4 (extra) Diamond Cap Jewels.

A friend in Boston who has a vast inventory of Waltham materials and has had many friends from the American Watch co. told me that there were these "wrinkles" of production that were sometimes turned out to make deliveries. You have a very rare example of a factory short term "revision".

what price I can put on that one.
the serial # shows that one to be 23 jewels watch so perhaps they made that one with 2 jewels less
and did the plug to have correct jewels count on plate?

Can not tell you much on what it would be worth Peter, but I am just wondering if it could have been up-jewelled from a run of 19 Jewel Vanguards from the factory, although the serial number looks to early, as I think the 19 jewel Vanguards' don't appear until after the 11 or 12 millions, someone else might be a little more knowledgeable with regard to that.

Your example looks like it is from a run in the 10 millions, this plugging occurred sporadically in early Vanguard runs from memory but more regularly after the 10 million mark, this plugging also occurred with some Appleton Tracy Movements in 17 & 21 Jewel. Another interesting observation is that the plug for the jewel count is gold in colour, all I have seen previously were nickel.

So it has been probably down-jewelled from the 23 -21 as David has alluded to, either way it has gone still a very interesting watch.

Cheers

What's it gonna take to buy it, Peter?

thanks all.