Battery Tray?

[truckster]

I decided that I would replace my battery tray when I pull the motor, since it's never been there. The PO had put a piece of plywood supporting the battery, and I expected the radiator support and fender would be totally rusted out.

I was surprised by what I saw; it really doesn't look too bad. I think I may only need the tray, something like this:

http://www.autoobsession.com/battery...hevytruck.aspx

It says it's a 3-hole mount, but I don't see where it mounts. Is it supposed to be welded in, or are there just bolt holes I'm missing?