Hiya welcome to the board. Cut top AND bottom usually point at a reworked item as in production terms it makes no sense to have both. There are exceptions of course. Red glass usually points at one of three major makers: Reijmyre, WMF and Whitefriars. And if all of those are discarded, try Empoli, Friedrich, Sarner and suchlike.
Good luck - it is a vast field....