depends where your welding, are you talking sliders, Matt? yea they are close there.. i would pull them away the frame's not that thick.
As for disconnecting the battery, if your TIG welding is a MUST!!
I've MIG and stick welded on my truck w/o an issue, I personally know people who have fried a battery though.
Honestly, it takes like 5 seconds to pull the neg. terminal off, just play it safe.