Did you get a back for it? That's kind of necessary.
The body does need a battery, the one in my Super body is a 4G13. I don't know how hard those are to get--the Super came with it & I bought the battery with my Pro body from KEH.
The 1000s back is fixed, although you can get extra inserts.
As for the battery, here is one list of equivalencies: 4LR44, 537, 2CR1/3N, 4SR44, 544, PX28, PX28L, V28PX, L544, 28SO, 4G13, 2CR1/N3, A544, 4SR44 PX28 4G13 V28PX and S28PX
The plethora of designations arises because of the large number of manufacturers who made this battery, among other things.
In some cases, the designations are particular to the type of battery (alkaline vs. silver oxide or lithium).
Matt