The vast majority of the cars will be sourced from the mfrs, some distributed by a dealer. Some are bought by Hertz. These are the ones that tend to stay on fleet up to 2 years these days, and others (most of the prestige ones) are on short term leases, and are recalled by the mfr after typically 6 months, of sometimes when they want them back.

Anything without a barcode is not a regular car, and is most likely, as Cymro says, an HLE owned car.

Many of the cars now have Dollar and Hertz personalities and two sets of barcodes on the keys and on the cars. The clue as to their heritage usually comes when you findthe paperwork in the glovebox.