I believe you're correct. In LBAPI documentation examples that illustrate the temporal data model show a gap when artifacts were moved to a recycle bin and later restored, or display no data after artifacts were moved to recycle bin and never restored.
Per this SO post, Lookback API doesn't provide anything along the lines of tracking entries in the Recycle Bin.
As far as Ready flag, a query like this will return the field value:
https://rally1.rallydev.com/analytics/v2.0/service/rally/workspace/12352608129/artifact/snapshot/query.js?find={"ObjectID":{$in:[16483705391,14167827399]}}&fields=["Name","Ready"]
e.g.
{
Name: "my story",
Ready: false
},
{
Name: "my story",
Ready: true
},
and this query will return results if value true
is treated as Boolean, not string, as SRMelody pointed out:
https://rally1.rallydev.com/analytics/v2.0/service/rally/workspace/12352608129/artifact/snapshot/query.js?find={"Ready":true}&fields=true