Do I really need a shift fork gauge?

I stripped my Pan transmission down so I now just have the case with the mainshaft stuff still in it. I'll be bringing it to a shop this weekend to have a really worn out main drive gear bushing replaced along with the seals, etc.

When I get it back, I'll be putting it back together myself. Do I absolutely need one of those shift fork gauge rigs to get the shift timing right? If so, maybe I'll just have the shop do it instead of buying one.

[Pa]

You do if you don't already have a sectioned off top assembly to use as a gauge. I can't think of any other way to do it. Pa