1.) no, you need to have at least the transactions up to the point in time, where you stored the wallet.dat file. Without sync there is no blockchain, then there is no data, from which core can read the amount.
2.) no. without blockchain data, there is no "database" to collect the amounts for the address.
There might be a work around for you: try to extract the bitcoin address from the wallet (or the bitcoin app shows you the address), and enter it into blockchain.info. They have a blockchain and the web-api, and can show all amounts, that were collected on a bitcoin address.