My 1099B does not have an acquired date. However I have the original trade confirmation document. Should I use that date?

Yes, use the trade date from the purchase confirmation.

In most cases, the basis should be the purchase price from the purchase confirmation.

The preceding assumes that you purchased the investment yourself or received it as a gift. If you inherited it, then for the date acquired enter the word "Inherited" instead of a date. The basis for an inherited investment is the market value on the date of death of the person you inherited it from.