Tokky

Hi Can anyone help? I have inherited a collection of 78 rpm records and amongst them is an Emidisc which doesn't have a proper label on - which I understand can be a studio or other cut? It simply has Emidisc and E.M.I Sales and Service Ltd written in green around the central spindle hole. I'd like to play it but I'm not sure what speed. It says 43 on one side of the central spindle hole and 51 on the other ... does this indicate that it's a 45 rpm? It's a 10" disc. thanks