Fully verifying nodes

Page 7 of the whitepaper at https://xx.network/xx-whitepaper-v1.3.pdf says
“By sampling a subset of the network to receive, verify, and endorse the transactions in a block, the majority of nodes only need to receive a condensed ledger of all transactions along with the endorsement of the sampled nodes.”

Does that mean that there are no fully verifying nodes in the XX network?
Not even the possibility of ones?
Will there be a way to request an arbitrary block from the entire history from nodes in the network?

Is this question more appropriate for the Node Technicals section?