I kinda agree and disagree...
Agree in that when there's no conversation of an expected timeline, it's impossible to say what each party had in mind.
Disagree in that I kinda think it should be standard to try to get art to someone before the paypal expiry window (45d) if that's how they're paying, just because that seems like a reasonable "default deadline" to me. Unless it's a really huge piece or there's some agreement otherwise, of course.