Pocket watch info

Movement is Omega calibre 38.5L, 15-jewels. Case by Dennison, 9 karat gold (.375), hallmarked Birmingham, England, circa 1939-40. Made for the market in Great Britain. Your movement became calibre 160, but yours has the calibre # 38.5L marked beneath the balance wheel. Bi-metallic, temperature compensating balance wheel, blued steel Breguet (overcoil) hairspring. I suspect it has a vitreous enamel dial, but hard to tell from your picture. Looks to be in premium condition.

Not much more to add to that.
Dial IMO is vitreous enamel ("porcelain") with Breguet style blued steel hands and Arabic numerals in Breguet or Omega "Paris" style.

A very nice example.

Porcelain has CLAY, KAOLIN, and FELDSPAR as ingredients. Porcelain is used in some clock dials, but I’m not aware it has ever been used in watches. Vitreous enamel is glass! No clay, kaolin, or feldspar in vitreous enamel!

Now that you know what you have, I suggest you research on line to find out what prices folks are asking for equivalent models. It is worth what the market is prepared to pay, and that can be all over the yard! The case is 9-karat gold, or 37.5 % gold, 62.5 % base metal. Case alone likely weighs 20 grams or so. With gold at current prices. There are sites on line where you can calculate the value of the gold in the case, alone. But the condition of the watch is such that it most certainly should yield more than the value of the gold in the case. (Bear in mind that prices people ask for items does not always mean they sell the item for the price asked.) Definition? I don’t know how to answer your question about value.

That's why I added "porcelain" with the quoty thingos, as that's what many people (incorrectly) understand this type of dial to be.