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Been there, done that ✅— and you won’t find them. There also a lot of people on the internet looking. The window manufacturer offer long or lifetime warranties to sell widows. They know no one will be looking for parts in the first 5 years, and after that you won’t find them....
I have responded to a similar question to this one (at the following link at the end) where I have listed a few methods of identifying a window manufacturer without identifying tags, though it may take a bit of time to follow through. To add: if a seller and/or manufacturer has older records, the building's address may also help identify the window's quote/order number. link