Perhaps would be nice to know which motors you have, or pictures or something. But anyway you only need to open the motor if you have a 5 wire unipolar only motor to which may try to separate the medians, but i guess that is not the case.
If it does not have a connector, you can happily solder the wires to the motor ones and use shrink tubing to cover solder joints. I think its even better than using any connector.
If it does not have a connector, you can happily solder the wires to the motor ones and use shrink tubing to cover solder joints. I think its even better than using any connector.