Did the mole expect the rat to invite him onto the boat? How do you know?

Mole was unsure whether or not the Water Rat would invite him aboard. We know this because he rather "pettishly".

‘Hullo, Mole!’ said the Water Rat.
‘Hullo, Rat!’ said the Mole.
‘Would you like to come over?’ enquired the Rat presently.
‘Oh, its all very well to TALK,’ said the Mole, rather pettishly, he being new to a river and riverside life and its ways.