MEM timestamp examples are in wrong format: Human readable text, should be a uint64. How to calculate the uint64?

I am trying to set the Timestamp values in a MEM Asset:
The doc is here but is wrong:

Membership
A Membership
Field Type Description
ValidFrom Timestamp Example: Fri Nov 09 2018 09:00:00 GMT+1000 (AEST)
ExpirationTimestamp Timestamp Example: Fri Nov 09 2018 09:00:00 GMT+1000 (AEST)

When I to build the MEM Asset with such text values, I get this error from Build --hex:
"Error: Failed to unmarshal MEM json file: json: cannot unmarshal string into Go struct field Membership.ValidFrom of type uint64

The examples should be uint64 values, apparently in nanoseconds.

What is the algorithm to calculate the uint64 Timestamp values???
Is it linux epoch time since jan 1, 1970?

The example values are misleading and the Timestamp link doesn’t seem to be working right now. It should go to https://tokenized.com/docs/protocol/assets#field-aliases

They are unsigned 64 bit integers representing nanoseconds since Unix Epoch. So basically standard unix timestamps times a billion.