I bought a Rattmotor 2.2kw spindle from Amazon, grounding

[Desertboy]

Hi, bought a spindle from Amazon because I bought one from ebay and then a week passed and then they refunded me the money so I paid the extra to get next day. Seems a lot better quality than the last spindle, better sockets, weighs 1kg moor and feels better machined,

They sent me this message



The only thing I already probed the 4 pins and there is continuity between pin 4 and the body so I cracked the aviation plug off and this has a proper GX25 on it rather than the custom 20mm they normally have and low and behold there's an earth wire connected to pin 4 going into the spindle body somewhere I couldn't see where

pins 1, 2, & 3 have no continuity to the body only to each other

So it's actually grounded even though they emailed specifically to tell me it's not, right?

And I should connect pin 4 to earth?