Not true. Speakers will make a noise if wired either way but it wont be how it should.
When they get a bass note the cone should kick forward (sending the sound forward), if wired the wrong way, the cone will kick backwards and youll still here it but the sound will be wrong.
Also, if you get one wired correctly and one wrong, the speakers will cancel each other out massively and youll lose bass.
Sorry.
The best way to check, is this.
Mark which colour wire is on which terminal of the originals. When you take the originals out, connect an AA battery to the terminals. When the + of the battery goes to the + of the speaker, the cone will push forwards. As you know which speaker wire was on which terminal, you can now work it out.
Hope that makes sense.