In that style of cab (older) it would likely be the alnico Marslands; if paired with that haed I must assume large magneet version (50 watts each vs 20). They are my fave guitar speaker (I have not tried them for bass) though the cone/surround can vary - doped cloth accordion surround with ribbed cone is my flavour of choice.
I started a spreadsheet of Marsland speakers but I haven't been able to figure out the model number code yet; not enough data. If you'd like to contribute to the effort, send me some pics of the speaker cone and rear basket.