ItemLookup using Amazon Product API

How can I look up one specific item. I'm not trying to lookup the product using the ASIN, I want to the exact product using the OfferListingId

The API keeps returning the error:

 [Message] => 9FKKDHB9XOBXVQWPMCJQF%2F6AF69WZCTZ76LD6TX2JWIW1QHSOW0XZWOSZ3HX%2B1GVPWXW%2FNKWAQWHRIZKG34SW3AXSZMUDGA%2FMT0WLVCKXJDORBPI0%2FMDSW%3D%3D is not a valid value for ItemId. Please change this value and retry your request.

This is the ID returned by a search I performed via the API.

I have the IDType set like this:

"IdType" => "ASIN",

The docs state:

Default: ASIN

Valid Values: SKU | UPC | EAN | ISBN

So, am I to believe that I can't do an itemLookup using their own internally assigned OfferListingId?