6 lug axle width?

[rbruno68]

I am considering picking up a 67-70 truck frame that is just a rolling chassie. I am really only interested in the axles to switch out in my 63 housing to get the 30 splines. There is no cab so I can't confirm the year, but it is 6 lug. Just want to confirm that any 6 lug 12 bolt axles will be compatible with a 63 housing? I know the rears got wider later, but not sure if that happened with the 5 lug switch or were there any 6 lug axles that were in wider housings. If that is the case, I probably won't take the chance.

Rob