Ah, OK. actually, electrically, does not matter. Make certain, though, that you take the time to electrically check continuity. Neither one of these should show continuity to ground. There have been many of these that has been poorly rebuilt with one brush shorted due to bad / broken or missing hardware. Here's what this does:
If you get the blue hooked to the grounded brush, you burn up the harness
If you get the green hooked to the brounded brush, it overcharges to beat heck!!!