Per your description, it won't work.
The timestamp parameter is ts. So for it to work you need:
- To put a correct timestamp value in ts parameter
- Make sure your report suite is at least timestamp optional (means that both manually timestamped hits and non timestamped hits can be processed) or timestamp enabled (only manually timestamped hits will be processed).
I would advise you to look at data insertion API
Also make sure that visitor id is the same.
And no there should not be a window as far as I know.