Robert,
I checked my moulds and H & G, Modern Bond and Cramer all used this type of design. On all the H & G's and MB's I have, the mould number or manufacture is stamped on the size of the mould. The Cramers have the stamps on the sprue plate. I can email you a picture of a cramer sprue plate and the screws that will be actual size. marmil at pacwest dot net.
Mark