Yes, it is just a temporary dip stick as the J2 has no provision in the prop shaft shroud to access a dip stick. But before fitting the diff I made up a temporary dipstick and measured where the oil would register on it when at the level of the top of the teeth on the crown wheel so that I can carefully add oil to the minimum level required to try and avoid it slurping down the axle casing to the hubs.
As for the gloves, you’d better speak to his mother about that