Silvertone 1457: trani wiring?

[nee]

Further examination of the Silvertone 1457 described in an earlier thread shows what seems to be something weird about the wiring of the power transformer.

There are two yellow leads for the heaters, no probs. There's a green lead.

Now, the schematic calls for the black leads to go to pins 1 and 6 of the 6X4 rectifier. On my amp, pins one and 6 are jumpered. One black lead goes to pin 6. The other black lead is tied to the green lead, which goes to earth, and then is jumpered to pin 2 of the 6X4.

Is this normal? Or safe??

Thanks!