No, there have been mixed results doing this and the schematic is not clear. There are stories of damage trying this.
Yes, it is intended to output 5V to power some sensors but putting 5V into it may back feed and cause a failure.
You can put 5V into the two prong battery input, though.
@jip The recommended battery is this:
Panasonic Lithium Ion 18650 3.7V, 3400Mah
You can put 5V into the two prong battery plug and the regulator will bring it down to 3.3.
The unit will still work, somewhat @ 3v.
