If they still aren't sure about gender and/or name, you could still buy an item for the shower and pay for the monogramming.
Most of these also offer engraving and/or monogramming.
Towels-Personalize towels or towel sets with embroidery or monogramming make great gifts.
A charge is usually placed on the monogramming since it takes extra work.
These charges are usually are done per character or line, although some places or items may only charge a flat rate for monogramming.