Using a drawbar like that is dangerous unless you cover the exposed pin solder joint.
Tethers are straight through wiring so reversing a BC-0000217 is no problem.
Since you said your doing this to PS-2 3V engine, almost all of the standard steam use the BC-0000217 external harness to start with, so you can just look and reverse it with that you have. The only issue maybe that the straight end does not have full outer rubber jacket. (Production harness are custom made at the factory).
If you want the covered look buy the BC-217.
PS-2 5V usually are custom wired and do not use the internal/external setup as shown by pennsy. So replacing those require one of the universal harnesses which you splice in with solder. G
