Did Waltham make many of the two tone in the 16sz model 1888?

Yup - it is in need of a serious cleaning

and a case screw missing

Waltham did that two-tone pattern on the M88 Riverside ...

... and the M83 Appleton, Tracy & Co.

So, does anyone have a ballpark # of the two-tone pattern type made in the 16sz Riverside 1888?

Jon, not many and I am sure not more than 1 or so with an added case screw like yous has.

David,

We call that screw a "special" touch from the previous owner...

Jon, this oversize 16-1/2 model; 1888 movement was originally held into the case with an alignment pin from the movement into the case body and one case screw to secure it as shown in Eric's magnificent picture above and my rather pedestrian picture of mine below.

Evidently some past watchmaker who cased it in the swing ring case machined a second case screw pocket in the train plate and then drilled and tapped the dial plate to accept that.
The 0.015" increase in case diameter of the swing ring to accept the slightly larger movement is a no-brainer" so long as it has two case screws.

Ok... I am tracking! This movement should have only had one movement case screw and a pin on the original case to help lock it in place. Have not had a chance to mess around with this one yet. When I get back from Atlanta, I will post a picture of the what is under that remaining screw. You have peeked my interest!

Furthermore, are you stating this movement will NOT fit in a standard 16sz Hunter Case because it is roughly a 16 1/2?

Yup. it is a little oversize (0.015" or so).

Interesting observation, Eric's has 9-1/2 "Daisies" on the train plate but yours and mine have only 6! I guess ours were Damaskeened on "the other side of the tracks".