Some years ago I bought a collection of mainly Webley items from the now defunct Cullens gun shop of lee On Solent, amongst which was a glass Webley oil bottle, the first publicly known about, along with a Webley flyer from 1946 announcing the introduction of these temporary glass oil bottles.
This one had a cork stopper, as did some of those subsequently discovered, but then several screw top bottles appeared, such as the one in Tim Dyson's boxed Senior.
I don't know how many of theses glass oil bottles have now come to light, but I would guess it's now just in double figures, but they are still an extremely scarce item, along with the earlier Webley Valvespout oil can.