What a beautiful little bird! I do believe he's a boy. He is a stunning shade of green!
Congratulations on your new addition
I just wanted to point out that sandpaper covers for perches are not recommended because they hurt the bottom of budgie feet and cause to conditions like bumble foot and painful sores. To keep his nails nice and trim, a variety of perches with different textures and diameters, especially natural wood ones, will help.
Also, be sure to remove any toys or metal components that have rust on them, as it could lead to heavy metal poisoning if they ingest any of it
He looks like a very happy little bird! We hope to see lots more of him around here