Yes, that is right. In one of Wodehouse's many novels, Bertie Wooster is attempting to master the banjolele, which he had heard in a jazz band.

I've never figured out when exactly Bertie was supposed to have flourished, have you, Afficionado? The late 1920's or early '30's, though no ugly reality such as the stock market crash or the Depression is allowed in Bertie's world.

!920's jazz bands used the banjo as a rhythm instrument. (They also used violins.) The banjolele would have been an offshoot of that.

I suppose you tune it like a ukelele.