Will my old references still matter if the new owner wants to check my history?

If you're continuing in your existing job through the sale, there generally isn't a fresh "reference check" the way there would be for an outside job applicant — the new owner already has direct access to your actual employment history and performance within the business, a far more reliable source than an outside reference call.

Where old references might come up is if the new owner is genuinely treating your continued employment as a new hiring decision, for instance in some asset-sale situations where employees are technically re-hired by a new corporate entity — and even then, your actual track record working in that same business should carry more weight than anything a third party could say about you. If you're worried about something specific in your history, that concern usually isn't really about the sale itself, since your performance within this business is directly observable to the new owner regardless of outside references.

If the new owner does ask for outside references as part of a genuine re-hiring process, it's fair to ask exactly why, given that your work history here already speaks for itself.