I've never seen a C152 without a step, BUT unless it had been pointed out, you might not realise it was there; it's not obvious. In any case, unless the tanks are full, it's hard to tell how much fuel you've got without a dipstick - and I've never seen a C152 with one of those. According to an instructor who'd worked it out, if I can just touch fuel with a fully extended finger in the tank, that'll be about three-quarters full; his fingers were longer and measured down to half tanks! Not the most scientific way of checking...but it's worked so far.
And before anyone criticises that comment, I fly with full tanks whenever physically and legally possible.