The spreadsheet doesn't have much wrong information
The VIN ending in 156138 for 2023 is a 1LT Convertible as you noticed. The VIN on that title is not real,
https://experience.gm.com/ownercente...FK1R60P0156138
There is no information from GM, normally a real VIN will 'decode' through that site for recall/warranty check for example mine:
https://experience.gm.com/ownercente...FH1R78N0102770
He's most likely got a stolen car.