The s/c accessory drive assembly A90550 bolts into rear of chain case on the left hand side. The drive should be painted black. Gasket 90552 goes between the accessory drive and the chain case spacer.
Accessory drive is secured with total of three bolts SA506, SA508 and SA608. Note that the upper hole is slotted to allow the drive to pivot and take up the slack in the timing chain.
Bolt finish is Parkerized dark, typically with heads marked W or 30 and lock washers as appropriate.