Answer:
To confirm the exact piece that you have a picture would be helpful. I do not know what is meant by "CASSEROL STICK TYPE". buty my guess is that you are referring to the single handle found on the butter warmer, marmite and gravy boat rather than the double handles found on the casseroles. I don't have these covers readily available to measure, but the 5 3/4" lid measurement helps narrow down the options. If the piece has a single handle then you apparently have gravy boat as the marmite and butter warmer lids are smaller. If your piece has two handles then you must have a 1 quart casserole because the 2 quart casserole lid is larger.

To answer your question regarding when the knob was placed on the cover I contacted another collector. Cassrole and gravy lids were produced using two molds. If your piece is one of the casserole lids or a gravy lid, there is an area with incised cross-hatched lines on both of the molds. These cross-hatched areas are where liquid slip would have been applied to both pieces before firing to secure them together.

Larry