Yes. Customers can opt in to the Google Customer Reviews survey at any point after their purchase, even if their order was placed weeks ago.
How it works
When a customer clicks "Yes" on the opt-in prompt (for example, after you've sent them a link to their order status page), the app pulls the original order details, including the order date, email address, and delivery country and passes them to Google along with an estimated delivery date.
The estimated delivery date is calculated from the original order date plus your Average delivery days setting.
For an older order, this date will already be in the past. Since Google sends the survey after the estimated delivery date has elapsed, and that date has long since passed, Google should send the survey relatively quickly after the customer opts in.
There's no additional waiting period for the delivery window as it has already been met.
Is there a cut-off for how old an order can be?
Google doesn't publish whether there's a maximum age for orders after which they'll stop sending surveys. This is managed entirely on Google's side and is outside of what our app can control.
We do not, however, recommend that you should solicit reviews from customers who placed their order months ago. Store ratings are built from enough unique Google Customer Reviews for a country within the last 12 months, so any reviews you receive for orders older than that will probably not count. Sending links to customers from years back so they opt-in retroactively could be deemed as review backfilling.
Google could treat that as trying to manipulate the programme, and it would be your GMC account at risk, not just the reviews, so we advise you not to pursue that as a strategy.
Things to keep in mind
The opt-in prompt will appear on the order status page regardless of when the customer visits it, as long as the checkout block is enabled and the order has an email address associated with it.
If a customer has previously dismissed the prompt by clicking "No," it won't reappear on the Thank You page for that session. However, it will appear again if they revisit the order status page at a later date.