Nipples can be hard to see especially when they're fluffy and young. I am not so sure - but am less experienced in dwarf hamsters. But I do remember incidences of it being very hard to tell with regards to how close the openings are. He/she is still quite young so maybe more will show over time. This might help and looking at this he could possibly be male!
https://www.wikihow.com/Determine-th...-Dwarf-Hamster