I already had my other cars insured through Erie Insurance and they were able to add it without much problem. It's $500 a year full coverage added on with two other cars. Oddly, the liability is most of that and more than either of my other two cars, but price was right overall so I wasn't going to quibble.
Ended up with Progressive and same issue with the VIN. Good to go now though! Okayish cost, but I tend to get a lot more insurance than I need. Thanks everyone!