Art...If the shop doesn't have the jig with the pucks to align with I think I would pass on letting them weld it back together.
I have a guy local to me who narrows rears with all of the jigs for different ones. He said he has to use the press on most housings to get them straight in order to re-weld them back together with the tubes and bearing races in line.
If when they press the tube and axle apart the backing plate gets damaged I may have an extra one of those around also.
Different years are slightly different even though they may both be 10x2.
When you source a housing be sure it is from a 65. I'm pretty sure 66-67 are a little wider with 68-70 being slightly wider yet. You may be able to call DR. Diff and Cass may know...